The Mizar article:

The Field of Complex Numbers

by
Anna Justyna Milewska

Received January 18, 2000

Copyright (c) 2000 Association of Mizar Users

MML identifier: COMPLFLD
[ MML identifier index ]


environ

 vocabulary COMPLEX1, ARYTM, VECTSP_1, RLVECT_1, COMPLSP1, BINOP_1, LATTICES,
      FUNCT_1, ARYTM_1, RELAT_1, ARYTM_3, ABSVALUE, COMPLFLD, XCMPLX_0;
 notation TARSKI, XBOOLE_0, SUBSET_1, STRUCT_0, ORDINAL1, NUMBERS, ARYTM_0,
      XCMPLX_0, XREAL_0, REAL_1, BINOP_1, ABSVALUE, RLVECT_1, VECTSP_1,
      COMPLSP1, COMPLEX1, FUNCT_1;
 constructors REAL_1, ABSVALUE, VECTSP_1, COMPLSP1, DOMAIN_1, BINOP_1,
      COMPLEX1, MEMBERED, ARYTM_0, ARYTM_3, FUNCT_4;
 clusters VECTSP_1, RELSET_1, XREAL_0, COMPLEX1, MEMBERED;
 requirements NUMERALS, SUBSET, BOOLE, ARITHM;
 definitions RLVECT_1, VECTSP_1;
 theorems STRUCT_0, COMPLEX1, RLVECT_1, BINOP_1, COMPLSP1, VECTSP_1, XREAL_0,
      XCMPLX_0, XCMPLX_1, ARYTM_0;

begin

canceled;

  theorem Th2:
   for x1,y1,x2,y2 be Element of REAL holds
    [*x1,y1*] + [*x2,y2*] = [*x1 + x2,y1 + y2*]
     proof
      let x1,y1,x2,y2 be Element of REAL;
      thus [*x1,y1*] + [*x2,y2*] =
       [*Re[*x1,y1*] + Re[*x2,y2*],Im[*x1,y1*] + Im[*x2,y2*]*] by COMPLEX1:def
9
       .=[*x1 + Re[*x2,y2*],Im[*x1,y1*] + Im[*x2,y2*]*] by COMPLEX1:7
       .=[*x1 + x2,Im[*x1,y1*] + Im[*x2,y2*]*] by COMPLEX1:7
       .=[*x1 + x2,y1 + Im[*x2,y2*]*] by COMPLEX1:7
       .=[*x1 + x2,y1 + y2*] by COMPLEX1:7;
     end;

  definition
   func F_Complex -> strict doubleLoopStr means :Def1:
    the carrier of it = COMPLEX &
    the add of it = addcomplex &
    the mult of it = multcomplex &
    the unity of it = 1r &
    the Zero of it = 0c;
   existence
   proof
    take doubleLoopStr (# COMPLEX,addcomplex,multcomplex,1r,0c #);
    thus thesis;
   end;
   uniqueness;
  end;

  definition
   cluster F_Complex -> non empty;
   coherence
   proof
      the carrier of F_Complex is non empty by Def1;
    hence F_Complex is non empty by STRUCT_0:def 1;
   end;
  end;

definition
  cluster -> complex Element of F_Complex;
  coherence
  proof
    let c be Element of F_Complex;
     the carrier of F_Complex is non empty by Def1;
    then c in the carrier of F_Complex;
    then c in COMPLEX by Def1;
    hence thesis by XCMPLX_0:def 2;
  end;
end;

  definition
   cluster F_Complex -> add-associative right_zeroed right_complementable
         Abelian commutative associative left_unital
         right_unital distributive Field-like non degenerated;
   coherence
   proof
    thus F_Complex is add-associative
     proof
      let x,y,z be Element of F_Complex;
      reconsider x1=x, y1=y, z1=z as Element of COMPLEX by Def1;
      thus (x + y) + z = (the add of F_Complex).[x + y,z1] by RLVECT_1:def 3
         .= (the add of F_Complex).[(the add of F_Complex).[x1,y1],z1]
                                                            by RLVECT_1:def 3
         .= addcomplex.[(the add of F_Complex).[x1,y1],z1] by Def1
         .= addcomplex.[addcomplex.[x1,y1],z1] by Def1
         .= addcomplex.(addcomplex.[x1,y1],z1) by BINOP_1:def 1
         .= addcomplex.(addcomplex.(x1,y1),z1) by BINOP_1:def 1
         .= addcomplex.(x1 + y1,z1) by COMPLSP1:def 1
         .=(x1 + y1) + z1 by COMPLSP1:def 1
         .= x1 + (y1 + z1) by XCMPLX_1:1
         .= addcomplex.(x1,y1 + z1) by COMPLSP1:def 1
         .= addcomplex.(x1,addcomplex.(y1,z1)) by COMPLSP1:def 1
         .= addcomplex.[x1,addcomplex.(y1,z1)] by BINOP_1:def 1
         .= addcomplex.[x1,addcomplex.[y1,z1]] by BINOP_1:def 1
         .= addcomplex.[x1,(the add of F_Complex).[y1,z1]] by Def1
         .= (the add of F_Complex).[x1,(the add of F_Complex).[y1,z1]] by Def1
         .= (the add of F_Complex).[x1,y + z] by RLVECT_1:def 3
         .= x + (y + z) by RLVECT_1:def 3;
     end;
    thus F_Complex is right_zeroed
     proof
      let x be Element of F_Complex;
      reconsider x1=x as Element of COMPLEX by Def1;
      thus x + 0.F_Complex =(the add of F_Complex).[x1,0.F_Complex]
                                                            by RLVECT_1:def 3
         .= (the add of F_Complex).(x1,0.F_Complex) by BINOP_1:def 1
         .= (the add of F_Complex).(x1,the Zero of F_Complex)
                                                            by RLVECT_1:def 2
         .= (the add of F_Complex).(x1,0c) by Def1
         .= addcomplex.(x1,0c) by Def1
         .= x1 + 0c by COMPLSP1:def 1
         .= x by COMPLEX1:22;
     end;
    thus F_Complex is right_complementable
     proof
      let x be Element of F_Complex;
      reconsider x1=x as Element of COMPLEX by Def1;
      reconsider y=-x1 as Element of F_Complex by Def1;
      take y;
      thus x + y = (the add of F_Complex).[x,y] by RLVECT_1:def 3
         .= (the add of F_Complex).(x,y) by BINOP_1:def 1
         .= addcomplex.(x1,y) by Def1
         .= x1+ -x1 by COMPLSP1:def 1
         .= 0c by XCMPLX_0:def 6
         .= the Zero of F_Complex by Def1
         .= 0.F_Complex by RLVECT_1:def 2;
     end;
    thus F_Complex is Abelian
     proof
      let x,y be Element of F_Complex;
      reconsider x1=x ,y1=y as Element of COMPLEX by Def1;
      thus x + y = (the add of F_Complex).[x1,y1] by RLVECT_1:def 3
         .= (the add of F_Complex).(x1,y1) by BINOP_1:def 1
         .= addcomplex.(x1,y1) by Def1
         .= y1 + x1 by COMPLSP1:def 1
         .= addcomplex.(y1,x1) by COMPLSP1:def 1
         .= (the add of F_Complex).(y1,x1) by Def1
         .= (the add of F_Complex).[y1,x1] by BINOP_1:def 1
         .= y + x by RLVECT_1:def 3;
     end;
    thus F_Complex is commutative
     proof
      let x,y be Element of F_Complex;
      reconsider x1=x ,y1=y as Element of COMPLEX by Def1;
      thus x * y = (the mult of F_Complex).(x1,y1) by VECTSP_1:def 10
         .= multcomplex.(x1,y1) by Def1
         .= y1 * x1 by COMPLSP1:def 4
         .= multcomplex.(y1,x1) by COMPLSP1:def 4
         .= (the mult of F_Complex).(y1,x1) by Def1
         .= y * x by VECTSP_1:def 10;
     end;
    thus F_Complex is associative
     proof
      let x,y,z be Element of F_Complex;
      reconsider x1=x, y1=y, z1=z as Element of COMPLEX by Def1;
      thus (x * y) * z = (the mult of F_Complex).(x * y,z1) by VECTSP_1:def 10
         .= (the mult of F_Complex).((the mult of F_Complex).(x1,y1),z1)
                                                            by VECTSP_1:def 10
         .= multcomplex.((the mult of F_Complex).(x1,y1),z1) by Def1
         .= multcomplex.(multcomplex.(x1,y1),z1) by Def1
         .= multcomplex.(x1 * y1,z1) by COMPLSP1:def 4
         .= (x1 * y1) * z1 by COMPLSP1:def 4
         .= x1 * (y1 * z1) by XCMPLX_1:4
         .= multcomplex.(x1,y1 * z1) by COMPLSP1:def 4
         .= multcomplex.(x1,multcomplex.(y1,z1)) by COMPLSP1:def 4
         .= multcomplex.(x1,(the mult of F_Complex).(y1,z1)) by Def1
         .= (the mult of F_Complex).(x1,(the mult of F_Complex).(y1,z1))
                                                                      by Def1
         .= (the mult of F_Complex).(x1,y * z) by VECTSP_1:def 10
         .= x * (y * z) by VECTSP_1:def 10;
     end;
    thus F_Complex is left_unital
     proof
      let x be Element of F_Complex;
       reconsider x1=x as Element of COMPLEX by Def1;
       thus (1_ F_Complex)*x =(the mult of F_Complex).(1_ F_Complex,x1)
                                                           by VECTSP_1:def 10
         .= multcomplex.(1_ F_Complex,x1) by Def1
         .= multcomplex.(the unity of F_Complex,x1) by VECTSP_1:def 9
         .= multcomplex.(1r,x1) by Def1
         .= 1r * x1 by COMPLSP1:def 4
         .= x by COMPLEX1:29;
      end;
    thus F_Complex is right_unital
     proof
      let x be Element of F_Complex;
       reconsider x1=x as Element of COMPLEX by Def1;
       thus x*(1_ F_Complex) =(the mult of F_Complex).(x1,1_ F_Complex)
                                                           by VECTSP_1:def 10
         .= multcomplex.(x1,1_ F_Complex) by Def1
         .= multcomplex.(x1,the unity of F_Complex) by VECTSP_1:def 9
         .= multcomplex.(x1,1r) by Def1
         .= x1 * 1r by COMPLSP1:def 4
         .= x by COMPLEX1:29;
      end;
    thus F_Complex is distributive
     proof
      let x,y,z be Element of F_Complex;
       reconsider x1=x, y1=y, z1=z as Element of COMPLEX by Def1;
       thus x*(y+z)=(the mult of F_Complex).(x1,y+z) by VECTSP_1:def 10
         .= (the mult of F_Complex).(x1,(the add of F_Complex).[y1,z1])
                                                           by RLVECT_1:def 3
         .= (the mult of F_Complex).(x1,(the add of F_Complex).(y1,z1))
                                                         by BINOP_1:def 1
         .= multcomplex.(x1,(the add of F_Complex).(y1,z1)) by Def1
         .= multcomplex.(x1,addcomplex.(y1,z1)) by Def1
         .= multcomplex.(x1,y1 + z1) by COMPLSP1:def 1
         .= x1 * (y1 + z1) by COMPLSP1:def 4
         .= x1 * y1 + x1 * z1 by XCMPLX_1:8
         .= addcomplex.(x1 * y1,x1 * z1) by COMPLSP1:def 1
         .= addcomplex.(multcomplex.(x1,y1),x1 * z1) by COMPLSP1:def 4
         .= addcomplex.(multcomplex.(x1,y1),multcomplex.(x1,z1))
                                                           by COMPLSP1:def 4
         .= (the add of F_Complex).(multcomplex.(x1,y1),multcomplex.(x1,z1))
                                                                     by Def1
         .= (the add of F_Complex).((the mult of F_Complex).(x1,y1),
                                               multcomplex.(x1,z1)) by Def1
         .= (the add of F_Complex).((the mult of F_Complex).(x1,y1),
                                   (the mult of F_Complex).(x1,z1)) by Def1
         .= (the add of F_Complex).[(the mult of F_Complex).(x1,y1),
                         (the mult of F_Complex).(x1,z1)] by BINOP_1:def 1
         .= (the add of F_Complex).[x * y,(the mult of F_Complex).(x1,z1)]
                                                          by VECTSP_1:def 10
         .= (the add of F_Complex).[x * y , x * z ] by VECTSP_1:def 10
         .= x*y+x*z by RLVECT_1:def 3;
       thus (y+z)*x = (the mult of F_Complex).(y+z,x1) by VECTSP_1:def 10
         .= (the mult of F_Complex).((the add of F_Complex).[y1,z1],x1)
                                                           by RLVECT_1:def 3
         .= (the mult of F_Complex).((the add of F_Complex).(y1,z1),x1)
                                                          by BINOP_1:def 1
         .= multcomplex.((the add of F_Complex).(y1,z1),x1) by Def1
         .= multcomplex.(addcomplex.(y1,z1),x1) by Def1
         .= multcomplex.(y1 + z1,x1) by COMPLSP1:def 1
         .= (y1 + z1) * x1 by COMPLSP1:def 4
         .= y1 * x1 + z1 * x1 by XCMPLX_1:8
         .= addcomplex.(y1 * x1,z1 * x1) by COMPLSP1:def 1
         .= addcomplex.(multcomplex.(y1,x1),z1 * x1) by COMPLSP1:def 4
         .= addcomplex.(multcomplex.(y1,x1),multcomplex.(z1,x1))
                                                           by COMPLSP1:def 4
         .= (the add of F_Complex).(multcomplex.(y1,x1),multcomplex.(z1,x1))
                                                                     by Def1
         .= (the add of F_Complex).((the mult of F_Complex).(y1,x1),
                                               multcomplex.(z1,x1)) by Def1
         .= (the add of F_Complex).((the mult of F_Complex).(y1,x1),
                                   (the mult of F_Complex).(z1,x1)) by Def1
         .= (the add of F_Complex).[(the mult of F_Complex).(y1,x1),
                      (the mult of F_Complex).(z1,x1)] by BINOP_1:def 1
         .= (the add of F_Complex).[y * x,(the mult of F_Complex).(z1,x1)]
                                                          by VECTSP_1:def 10
         .= (the add of F_Complex).[y * x , z * x ] by VECTSP_1:def 10
         .= y * x + z * x by RLVECT_1:def 3;
     end;
    thus F_Complex is Field-like
     proof
      let x be Element of F_Complex;
      assume A1: x <> 0.F_Complex;
      reconsider x1=x as Element of COMPLEX by Def1;
      reconsider y=x1" as Element of F_Complex by Def1;
      take y;
        x1<>the Zero of F_Complex by A1,RLVECT_1:def 2;
      then A2: x1<>0c by Def1;
      thus x * y = (the mult of F_Complex).(x1,x1") by VECTSP_1:def 10
         .=multcomplex.(x1,x1") by Def1
         .=x1 * x1" by COMPLSP1:def 4
         .=1r by A2,COMPLEX1:65
         .=the unity of F_Complex by Def1
         .=1_ F_Complex by VECTSP_1:def 9;
     end;
    thus F_Complex is non degenerated
     proof
      A3: 0.F_Complex = the Zero of F_Complex by RLVECT_1:def 2
                     .= 0c by Def1;
            1_ F_Complex = the unity of F_Complex by VECTSP_1:def 9
                     .= 1r by Def1;
      hence 0.F_Complex <> 1_ F_Complex by A3,COMPLEX1:12,15;
     end;
   end;
  end;

  theorem Th3:
   for x1,y1 be Element of F_Complex
   for x2,y2 be Element of COMPLEX st x1 = x2 & y1 = y2 holds
    x1 + y1 = x2 + y2
   proof
    let x1,y1 be Element of F_Complex;
    let x2,y2 be Element of COMPLEX;
    assume x1 = x2 & y1 = y2;
    hence x1 + y1 = (the add of F_Complex).[x2,y2] by RLVECT_1:def 3
         .= (the add of F_Complex).(x2,y2) by BINOP_1:def 1
         .= addcomplex.(x2,y2) by Def1
         .= x2 + y2 by COMPLSP1:def 1;
   end;

  theorem Th4:
   for x1 be Element of F_Complex
   for x2 be Element of COMPLEX st x1 = x2 holds
    - x1 = - x2
   proof
    let x1 be Element of F_Complex;
    let x2 be Element of COMPLEX;
    assume A1: x1 = x2;
    reconsider x3 = x1 as Element of COMPLEX by Def1;
      -x2 is Element of F_Complex by Def1;
    then reconsider x'=-x2 as Element of F_Complex;
      x1 + x' = x3 + -x2 by Th3
       .= 0c by A1,XCMPLX_0:def 6
       .= the Zero of F_Complex by Def1
       .= 0.F_Complex by RLVECT_1:def 2;
    hence thesis by RLVECT_1:def 10;
    end;

  theorem Th5:
   for x1,y1 be Element of F_Complex
   for x2,y2 be Element of COMPLEX st x1 = x2 & y1 = y2 holds
    x1 - y1 = x2 - y2
   proof
    let x1,y1 be Element of F_Complex;
    let x2,y2 be Element of COMPLEX;
    assume A1: x1 = x2 & y1 = y2;
    then A2: - y1 = -y2 by Th4;
    thus x1 - y1 = x1 + (-y1) by RLVECT_1:def 11
         .= x2 + (-y2) by A1,A2,Th3
         .= x2 - y2 by XCMPLX_0:def 8;
   end;

  theorem Th6:
   for x1,y1 be Element of F_Complex
   for x2,y2 be Element of COMPLEX st x1 = x2 & y1 = y2 holds
    x1 * y1 = x2 * y2
   proof
    let x1,y1 be Element of F_Complex;
    let x2,y2 be Element of COMPLEX;
    assume x1 = x2 & y1 = y2;
    hence x1 * y1 = (the mult of F_Complex).(x2,y2) by VECTSP_1:def 10
         .= multcomplex.(x2,y2) by Def1
         .= x2 * y2 by COMPLSP1:def 4;
   end;

  theorem Th7:
   for x1 be Element of F_Complex
   for x2 be Element of COMPLEX st x1 = x2 & x1 <> 0.F_Complex holds
    x1" = x2"
   proof
    let x1 be Element of F_Complex;
    let x2 be Element of COMPLEX;
    assume A1: x1 = x2 & x1 <> 0.F_Complex;
    A2: 0c = the Zero of F_Complex by Def1
       .= 0.F_Complex by RLVECT_1:def 2;
    reconsider x3 = x1 as Element of COMPLEX by Def1;
      x2" is Element of F_Complex by Def1;
    then reconsider x'= x2" as Element of F_Complex;
      x1 * x' = x3 * x2" by Th6
       .= 1r by A1,A2,COMPLEX1:65
       .= the unity of F_Complex by Def1
       .= 1_ F_Complex by VECTSP_1:def 9;
    hence x1" = x2" by A1,VECTSP_1:def 22;
   end;

  theorem Th8:
   for x1,y1 be Element of F_Complex
   for x2,y2 be Element of COMPLEX st
    x1 = x2 & y1 = y2 & y1 <> 0.F_Complex holds x1/y1 = x2/y2
   proof
    let x1,y1 be Element of F_Complex;
    let x2,y2 be Element of COMPLEX;
    assume A1: x1 = x2 & y1 = y2;
    assume y1 <> 0.F_Complex;
    then A2: y1" = y2" by A1,Th7;
    thus x1/y1 = x1 * y1" by VECTSP_1:def 23
              .= x2 * y2" by A1,A2,Th6
              .= x2/y2 by XCMPLX_0:def 9;
   end;

  theorem Th9:
   0.F_Complex = 0c
   proof
    thus 0c = the Zero of F_Complex by Def1
       .= 0.F_Complex by RLVECT_1:def 2;
   end;

  theorem Th10:
   1_ F_Complex = 1r
   proof
    thus 1r = the unity of F_Complex by Def1
       .= 1_ F_Complex by VECTSP_1:def 9;
   end;

  theorem
     1_ F_Complex + 1_ F_Complex <> 0.F_Complex
    proof
L1: 1r = [*1,0*] by ARYTM_0:def 7,COMPLEX1:def 7;
       1_ F_Complex = the unity of F_Complex by VECTSP_1:def 9
                .= [*1,0*] by Def1,L1;
     then A1: 1_ F_Complex + 1_ F_Complex =
            (the add of F_Complex).[[*1,0*],[*1,0*]] by RLVECT_1:def 3
         .= (the add of F_Complex).([*1,0*],[*1,0*]) by BINOP_1:def 1
         .= addcomplex.([*1,0*],[*1,0*]) by Def1
         .= [*1,0*] + [*1,0*] by COMPLSP1:def 1
         .= [*1+1,0+0*] by Th2;
L0: 0c = [*0,0*] by ARYTM_0:def 7;
        0.F_Complex = the Zero of F_Complex by RLVECT_1:def 2
                .= [*0,0*] by Def1,L0;
     hence thesis by A1,ARYTM_0:12;
    end;

  definition
   let z be Element of F_Complex;
   func z*' -> Element of F_Complex means :Def2:
    ex z' be Element of COMPLEX
    st z = z' & it = z'*';
   existence
    proof
     reconsider z'=z as Element of COMPLEX by Def1;
       z'*' is Element of F_Complex by Def1;
     then reconsider z1=z'*' as Element of F_Complex;
     take z1;
     take z';
     thus z = z' & z1 = z'*';
    end;
   uniqueness;
  end;

  definition
   let z be Element of F_Complex;
   func |.z.| -> real number means :Def3:
    ex z' be Element of COMPLEX st z = z' & it = |.z'.|;
   existence
    proof
     reconsider z'=z as Element of COMPLEX by Def1;
     take z1=|.z'.|;
     take z';
     thus z = z' & z1 = |.z'.|;
    end;
   uniqueness;
  end;

  definition
   let z be Element of F_Complex;
   redefine func |.z.| -> Element of REAL;
   coherence by XREAL_0:def 1;
  end;

  theorem Th12:
   for x1 be Element of F_Complex
   for x2 be Element of COMPLEX st
    x1 = x2 holds x1*' = x2*'
    proof
     let x1 be Element of F_Complex;
     let x2 be Element of COMPLEX;
     assume A1: x1 = x2;
     consider x3 be Element of COMPLEX such that
      A2: x1 = x3 & x1*' = x3*' by Def2;
     thus x1*' = x2*' by A1,A2;
    end;

reserve z,z1,z2,z3,z4 for Element of F_Complex;

canceled 16;

  theorem
     -z = (-1_ F_Complex) * z
    proof
     reconsider z'=z as Element of COMPLEX by Def1;
     A1: -1r = -1_ F_Complex by Th4,Th10;
     thus -z = -z' by Th4
            .= (-1r) * z' by COMPLEX1:46
            .= (-1_ F_Complex) * z by A1,Th6;
    end;

canceled 5;

  theorem
     z1 - -z2 = z1 + z2
    proof
     reconsider z1'=z1,z2'=z2 as Element of COMPLEX by Def1;
       -z2 = -z2' by Th4;
     hence z1 - -z2 = z1'- -z2' by Th5
             .= z1' + z2' by XCMPLX_1:151
             .= z1 + z2 by Th3;
    end;

canceled 5;

  theorem
     z1 = z1 + z - z
    proof
     reconsider z1'=z1,z'=z as Element of COMPLEX by Def1;
       z1 + z = z1' + z' by Th3;
     hence z1 + z - z = z1' + z' - z' by Th5
                    .= z1 by XCMPLX_1:26;
    end;

  theorem
     z1 = z1 - z + z
    proof
     reconsider z1'=z1,z'=z as Element of COMPLEX by Def1;
       z1 - z = z1' - z' by Th5;
     hence z1 - z + z = z1' - z' + z' by Th3
                    .= z1 by XCMPLX_1:27;
    end;

canceled 4;

  theorem
     z1 <> 0.F_Complex & z2 <> 0.F_Complex &
   z1" = z2" implies z1 = z2
    proof
     reconsider z1'=z1,z2'=z2 as Element of COMPLEX by Def1;
     assume A1: z1 <> 0.F_Complex;
     assume A2: z2 <> 0.F_Complex;
     assume z1" = z2";
     then z1'" = z2" by A1,Th7
              .= z2'" by A2,Th7;
     hence z1 = z2 by XCMPLX_1:202;
    end;

  theorem
     z2 <> 0.F_Complex &
    (z1 * z2 = the unity of F_Complex or z2 * z1 = the unity of F_Complex)
    implies z1 = z2"
    proof
     reconsider z1'=z1,z2'=z2 as Element of COMPLEX by Def1;
     assume A1: z2 <> 0.F_Complex;
     assume A2: z1 * z2 = the unity of F_Complex or
                z2 * z1 = the unity of F_Complex;
     per cases by A2;
      suppose z1 * z2 = the unity of F_Complex;
      then z1' * z2' = the unity of F_Complex by Th6;
      then A3: z1' * z2' = 1r by Def1;
        z2" = z2'" by A1,Th7;
      hence z1 = z2" by A1,A3,Th9,COMPLEX1:69;
      suppose z2 * z1 = the unity of F_Complex;
      then z2' * z1' = the unity of F_Complex by Th6;
      then A4: z2' * z1' = 1r by Def1;
        z2" = z2'" by A1,Th7;
      hence z1 = z2" by A1,A4,Th9,COMPLEX1:69;
    end;

  theorem
     z2 <> 0.F_Complex & (z1 * z2 = z3 or z2 * z1 = z3) implies
    z1 = z3 * z2" & z1 = z2" * z3
    proof
     reconsider z1'=z1,z2'=z2,z3'=z3 as Element of COMPLEX by Def1;
     assume A1: z2 <> 0.F_Complex;
     assume A2: (z1 * z2 = z3 or z2 * z1 = z3);
     A3: z2" = z2'" by A1,Th7;
     per cases by A2;
      suppose z1 * z2 = z3;
      then z1' * z2' = z3' by Th6;
      then z1' = z3' * z2'" by A1,Th9,XCMPLX_1:204;
      hence z1 = z3 * z2" & z1 = z2" * z3 by A3,Th6;
      suppose z2 * z1 = z3;
      then z2' * z1' = z3' by Th6;
      then z1' = z3' * z2'" by A1,Th9,XCMPLX_1:204;
      hence z1 = z3 * z2" & z1 = z2" * z3 by A3,Th6;
    end;

  theorem
     (the unity of F_Complex)" = the unity of F_Complex
    proof
       the unity of F_Complex <> 0c by Def1,COMPLEX1:12,15;
     then the unity of F_Complex <> the Zero of F_Complex by Def1;
     then A1: the unity of F_Complex <> 0.F_Complex by RLVECT_1:def 2;
       the unity of F_Complex = 1r by Def1;
     hence thesis by A1,Th7,COMPLEX1:71;
    end;

  theorem
     z1 <> 0.F_Complex & z2 <> 0.F_Complex implies
    (z1 * z2)" = z1" * z2"
    proof
     reconsider z1'=z1,z2'=z2 as Element of COMPLEX by Def1;
     assume A1: z1 <> 0.F_Complex;
     assume A2: z2 <> 0.F_Complex;
     A3: z1" = z1'" by A1,Th7;
     A4: z2" = z2'" by A2,Th7;
     A5: z1 * z2 <> 0.F_Complex by A1,A2,VECTSP_1:44;
       z1 * z2 = z1' * z2' by Th6;
     hence (z1 * z2)" = (z1' * z2')" by A5,Th7
                     .= z1'" * z2'" by XCMPLX_1:205
                     .= z1" * z2" by A3,A4,Th6;
    end;

canceled;

  theorem
     z <> 0.F_Complex implies (-z)" = -(z")
    proof
     reconsider z1=z as Element of COMPLEX by Def1;
     assume A1: z <> 0.F_Complex;
     then A2: z1" = z" by Th7;
A3:  -z <> 0.F_Complex by A1,VECTSP_1:86;
       -z = -z1 by Th4;
     hence (-z)" = (-z1)" by A3,Th7
                .= -(z1") by XCMPLX_1:224
                .= -(z") by A2,Th4;
    end;

canceled;

  theorem
     z1 <> 0.F_Complex & z2 <> 0.F_Complex implies
    z1" + z2" = (z1 + z2) * (z1 * z2)"
    proof
     reconsider z1'=z1,z2'=z2 as Element of COMPLEX by Def1;
     assume A1: z1 <> 0.F_Complex;
     then A2: z1" = z1'" by Th7;
     assume A3: z2 <> 0.F_Complex;
     then A4: z2" = z2'" by Th7;
     A5: z1 + z2 = z1' + z2' by Th3;
A6: z1 * z2 <> 0.F_Complex by A1,A3,VECTSP_1:44;
       z1 * z2 = z1' * z2' by Th6;
     then A7: (z1 * z2)" = (z1' * z2')" by A6,Th7;
     thus z1" + z2" = z1'" + z2'" by A2,A4,Th3
                    .= (z1' + z2') * (z1' * z2')" by A1,A3,Th9,XCMPLX_1:213
                    .= (z1 + z2) * (z1 * z2)" by A5,A7,Th6;
    end;

  theorem
     z1 <> 0.F_Complex & z2 <> 0.F_Complex implies
    z1" - z2" = (z2 - z1) * (z1 * z2)"
    proof
     reconsider z1'=z1,z2'=z2 as Element of COMPLEX by Def1;
     assume A1: z1 <> 0.F_Complex;
     then A2: z1" = z1'" by Th7;
     assume A3: z2 <> 0.F_Complex;
     then A4: z2" = z2'" by Th7;
     A5: z2 - z1 = z2' - z1' by Th5;
     A6: z1 * z2 <> 0.F_Complex by A1,A3,VECTSP_1:44;
       z1 * z2 = z1' * z2' by Th6;
     then A7: (z1 * z2)" = (z1' * z2')" by A6,Th7;
     thus z1" - z2" = z1'" - z2'" by A2,A4,Th5
                    .= (z2' - z1') * (z1' * z2')" by A1,A3,Th9,XCMPLX_1:214
                    .= (z2 - z1) * (z1 * z2)" by A5,A7,Th6;
    end;

canceled;

  theorem
     z <> 0.F_Complex implies z" = (the unity of F_Complex) / z
    proof
     reconsider z1=z as Element of COMPLEX by Def1;
     assume A1: z <> 0.F_Complex;
     A2: the unity of F_Complex = 1r by Def1;
     thus z" = z1" by A1,Th7
            .= 1r / z1 by A1,Th9,COMPLEX1:84
            .= (the unity of F_Complex) / z by A1,A2,Th8;
    end;

  theorem
     z / (the unity of F_Complex) = z
    proof
     reconsider z1=z as Element of COMPLEX by Def1;
       the unity of F_Complex = 1r by Def1;
     hence z / (the unity of F_Complex) = z1 / 1r by Th8,Th9,COMPLEX1:12,15
                                      .= z by COMPLEX1:85;
    end;

  theorem
     z <> 0.F_Complex implies z / z = the unity of F_Complex
    proof
     reconsider z1=z as Element of COMPLEX by Def1;
     assume A1: z <> 0.F_Complex;
     hence z / z = z1 / z1 by Th8
               .= 1r by A1,Th9,COMPLEX1:86
               .= the unity of F_Complex by Def1;
    end;

  theorem
     z <> 0.F_Complex implies (0.F_Complex) / z = 0.F_Complex
    proof
     reconsider z1=z as Element of COMPLEX by Def1;
     assume z <> 0.F_Complex;
     hence (0.F_Complex) / z = 0c / z1 by Th8,Th9
                            .= 0.F_Complex by Th9,COMPLEX1:87;
    end;

  theorem Th62:
   z2 <> 0.F_Complex & z1 / z2 = 0.F_Complex implies
    z1 = 0.F_Complex
    proof
     reconsider z1'=z1,z2'=z2 as Element of COMPLEX by Def1;
     assume A1: z2 <> 0.F_Complex;
     assume z1 / z2 = 0.F_Complex;
     then z1' / z2' = 0.F_Complex by A1,Th8;
     hence z1 = 0.F_Complex by A1,Th9,XCMPLX_1:50;
    end;

  theorem
     z2 <> 0.F_Complex & z4 <> 0.F_Complex implies
    (z1 / z2) * (z3 / z4) = (z1 * z3) / (z2 * z4)
    proof
     reconsider z1'=z1,z2'=z2,z3'=z3,z4'=z4 as Element of COMPLEX by Def1;
     assume A1: z2 <> 0.F_Complex;
     assume A2: z4 <> 0.F_Complex;
     A3: z1' * z3' = z1 * z3 by Th6;
     A4: z2' * z4' = z2 * z4 by Th6;
     A5: z2 * z4 <> 0.F_Complex by A1,A2,VECTSP_1:44;
     A6: z1' / z2' = z1 / z2 by A1,Th8;
       z3' / z4' = z3 / z4 by A2,Th8;
     hence (z1 / z2) * (z3 / z4) = (z1' / z2') * (z3' / z4') by A6,Th6
                       .= (z1' * z3') / (z2' * z4') by XCMPLX_1:77
                       .= (z1 * z3) / (z2 * z4) by A3,A4,A5,Th8;
    end;

  theorem
     z2 <> 0.F_Complex implies z * (z1 / z2) = (z * z1) / z2
    proof
     reconsider z1'=z1,z2'=z2,z'=z as Element of COMPLEX by Def1;
     assume A1: z2 <> 0.F_Complex;
     A2: z' * z1' = z * z1 by Th6;
       z1' / z2' = z1 / z2 by A1,Th8;
     hence z * (z1 / z2) = z' * (z1' / z2') by Th6
                       .= (z' * z1') / z2' by XCMPLX_1:75
                       .= (z * z1) / z2 by A1,A2,Th8;
    end;

  theorem
     z2 <> 0.F_Complex & z1 / z2 = the unity of F_Complex implies
    z1 = z2
    proof
     reconsider z1'=z1,z2'=z2 as Element of COMPLEX by Def1;
     assume A1: z2 <> 0.F_Complex;
     assume z1 / z2 = the unity of F_Complex;
     then z1' / z2' = the unity of F_Complex by A1,Th8;
     then z1' / z2' = 1r by Def1;
     hence z1 = z2 by A1,Th9,COMPLEX1:91;
    end;

  theorem
     z <> 0.F_Complex implies z1 = (z1 * z) / z
    proof
     reconsider z1'=z1,z'=z as Element of COMPLEX by Def1;
     assume A1: z <> 0.F_Complex;
     A2: z1' * z' = z1 * z by Th6;
     thus z1 = (z1' * z') / z' by A1,Th9,XCMPLX_1:90
            .= (z1 * z) / z by A1,A2,Th8;
    end;

  theorem
     z1 <> 0.F_Complex & z2 <> 0.F_Complex implies
    (z1 / z2)" = z2 / z1
    proof
     reconsider z1'=z1,z2'=z2 as Element of COMPLEX by Def1;
     assume A1: z1 <> 0.F_Complex;
     assume A2: z2 <> 0.F_Complex;
     then A3: z1 / z2 <> 0.F_Complex by A1,Th62;
       z1' / z2' = z1 / z2 by A2,Th8;
     hence (z1 / z2)" = (z1' / z2')" by A3,Th7
                     .= z2' / z1' by XCMPLX_1:215
                     .= z2 / z1 by A1,Th8;
    end;

  theorem
     z1 <> 0.F_Complex & z2 <> 0.F_Complex implies
    (z1" / z2") = z2 / z1
    proof
     reconsider z1'=z1,z2'=z2 as Element of COMPLEX by Def1;
     assume A1: z1 <> 0.F_Complex;
     assume A2: z2 <> 0.F_Complex;
     A3: z1" = z1'" by A1,Th7;
     A4: z2" = z2'" by A2,Th7;
       z2" <> 0.F_Complex by A2,VECTSP_1:74;
     hence (z1" / z2") = (z1'" / z2'") by A3,A4,Th8
                     .= z2' / z1' by XCMPLX_1:216
                     .= z2 / z1 by A1,Th8;
    end;

  theorem
     z2 <> 0.F_Complex implies z1 / z2" = z1 * z2
    proof
     reconsider z1'=z1,z2'=z2 as Element of COMPLEX by Def1;
     assume A1: z2 <> 0.F_Complex;
     then A2: z2" <> 0.F_Complex by VECTSP_1:74;
       z2" = z2'" by A1,Th7;
     hence z1 / z2" = z1' / z2'" by A2,Th8
                  .= z1' * z2' by XCMPLX_1:221
                  .= z1 * z2 by Th6;
    end;

  theorem
     z1 <> 0.F_Complex & z2 <> 0.F_Complex implies
    z1" / z2 = (z1 * z2)"
    proof
     reconsider z1'=z1,z2'=z2 as Element of COMPLEX by Def1;
     assume A1: z1 <> 0.F_Complex;
     assume A2: z2 <> 0.F_Complex;
     then A3: z1 * z2 <> 0.F_Complex by A1,VECTSP_1:44;
     A4: z1 * z2 = z1' * z2' by Th6;
       z1" = z1'" by A1,Th7;
     hence z1" / z2 = z1'" / z2' by A2,Th8
                   .= (z1' * z2')" by XCMPLX_1:223
                   .= (z1 * z2)" by A3,A4,Th7;
     end;

  theorem
     z1 <> 0.F_Complex & z2 <> 0.F_Complex implies
    z1"* (z / z2) = z / (z1 * z2)
    proof
     reconsider z1'=z1,z2'=z2,z'=z as Element of COMPLEX by Def1;
     assume A1: z1 <> 0.F_Complex;
     assume A2: z2 <> 0.F_Complex;
     then A3: z1 * z2 <> 0.F_Complex by A1,VECTSP_1:44;
     A4: z1" = z1'" by A1,Th7;
     A5: z1 * z2 = z1' * z2' by Th6;
       z' / z2' = z / z2 by A2,Th8;
     hence z1"* (z / z2) = z1'"* (z' / z2') by A4,Th6
                       .= z' / (z1' * z2') by XCMPLX_1:222
                       .= z / (z1 * z2) by A3,A5,Th8;
    end;

  theorem
     z <> 0.F_Complex & z2 <> 0.F_Complex implies
    (z1 / z2) = (z1 * z) / (z2 * z) & (z1 / z2) = (z * z1) / (z * z2)
    proof
     reconsider z1'=z1,z2'=z2,z'=z as Element of COMPLEX by Def1;
     assume A1: z <> 0.F_Complex;
     assume A2: z2 <> 0.F_Complex;
     A3: z1 * z = z1' * z' by Th6;
     A4: z2 * z = z2' * z' by Th6;
     A5: z2 * z <> 0.F_Complex by A1,A2,VECTSP_1:44;
     thus (z1 / z2) = (z1' / z2') by A2,Th8
                   .= (z1' * z') / (z2' * z') by A1,Th9,XCMPLX_1:92
                   .= (z1 * z) / (z2 * z) by A3,A4,A5,Th8;
     hence thesis;
    end;

  theorem
     z2 <> 0.F_Complex & z3 <> 0.F_Complex implies
    z1 / (z2 * z3) = z1 / z2 / z3
    proof
     reconsider z1'=z1,z2'=z2,z3'=z3 as Element of COMPLEX by Def1;
     assume A1: z2 <> 0.F_Complex;
     assume A2: z3 <> 0.F_Complex;
     A3: z2 * z3 = z2' * z3' by Th6;
     A4: z2 * z3 <> 0.F_Complex by A1,A2,VECTSP_1:44;
     A5: z1 / z2 = z1' / z2' by A1,Th8;
     thus z1 / (z2 * z3) = z1' / (z2' * z3') by A3,A4,Th8
                        .= z1' / z2' / z3' by XCMPLX_1:79
                        .= z1 / z2 / z3 by A2,A5,Th8;
    end;

  theorem
     z2 <> 0.F_Complex & z3 <> 0.F_Complex implies
    (z1 * z3) / z2 = z1 / (z2 / z3)
    proof
     reconsider z1'=z1,z2'=z2,z3'=z3 as Element of COMPLEX by Def1;
     assume A1: z2 <> 0.F_Complex;
     assume A2: z3 <> 0.F_Complex;
     then A3: z2 / z3 = z2' / z3' by Th8;
     A4: z2 / z3 <> 0.F_Complex by A1,A2,Th62;
       z1 * z3 = z1' * z3' by Th6;
     hence (z1 * z3) / z2 = (z1' * z3') / z2' by A1,Th8
                        .= z1' / (z2' / z3') by XCMPLX_1:78
                        .= z1 / (z2 / z3) by A3,A4,Th8;
    end;

  theorem
     z2 <> 0.F_Complex & z3 <> 0.F_Complex &
    z4 <> 0.F_Complex implies
    (z1 / z2) / (z3 / z4) = (z1 * z4) / (z2 * z3)
    proof
     reconsider z1'=z1,z2'=z2,z3'=z3,z4'=z4 as Element of COMPLEX by Def1;
     assume A1: z2 <> 0.F_Complex;
     assume A2: z3 <> 0.F_Complex;
     assume A3: z4 <> 0.F_Complex;
     A4: z1 * z4 = z1' * z4' by Th6;
     A5: z2 * z3 = z2' * z3' by Th6;
     A6: z2 * z3 <> 0.F_Complex by A1,A2,VECTSP_1:44;
     A7: z1 / z2 = z1' / z2' by A1,Th8;
     A8: z3 / z4 = z3' / z4' by A3,Th8;
       z3 / z4 <> 0.F_Complex by A2,A3,Th62;
     hence (z1 / z2) / (z3 / z4) = (z1' / z2') / (z3' / z4') by A7,A8,Th8
                   .= (z1' * z4') / (z2' * z3') by XCMPLX_1:85
                   .= (z1 * z4) / (z2 * z3) by A4,A5,A6,Th8;
    end;

  theorem
     z2 <> 0.F_Complex & z4 <> 0.F_Complex implies
    z1 / z2 + z3 / z4 = (z1 * z4 + z3 * z2) / (z2 * z4)
    proof
     reconsider z1'=z1,z2'=z2,z3'=z3,z4'=z4 as Element of COMPLEX by Def1;
     assume A1: z2 <> 0.F_Complex;
     assume A2: z4 <> 0.F_Complex;
     A3: z2 * z4 = z2' * z4' by Th6;
     A4: z1 * z4 = z1' * z4' by Th6;
       z3 * z2 = z3' * z2' by Th6;
     then A5: z1 * z4 + z3 * z2 = z1' * z4' + z3' * z2' by A4,Th3;
     A6: z2 * z4 <> 0.F_Complex by A1,A2,VECTSP_1:44;
     A7: z1 / z2 = z1' / z2' by A1,Th8;
       z3 / z4 = z3' / z4' by A2,Th8;
     hence z1 / z2 + z3 / z4 = z1' / z2' + z3' / z4' by A7,Th3
               .= (z1' * z4' + z3' * z2') / (z2' * z4') by A1,A2,Th9,XCMPLX_1:
117
               .= (z1 * z4 + z3 * z2) / (z2 * z4) by A3,A5,A6,Th8;
    end;

  theorem
     z <> 0.F_Complex implies z1 / z + z2 / z = (z1 + z2) / z
    proof
     reconsider z1'=z1,z2'=z2,z'=z as Element of COMPLEX by Def1;
     assume A1: z <> 0.F_Complex;
     A2: z1 + z2 = z1' + z2' by Th3;
     A3: z1 / z = z1' / z' by A1,Th8;
       z2 / z = z2' / z' by A1,Th8;
     hence z1 / z + z2 / z = z1' / z' + z2' / z' by A3,Th3
                         .= (z1' + z2') / z' by XCMPLX_1:63
                         .= (z1 + z2) / z by A1,A2,Th8;
    end;

  theorem
     z2 <> 0.F_Complex implies -(z1 / z2) = (-z1) / z2 &
    -(z1 / z2) = z1 / (-z2)
    proof
     reconsider z1'=z1,z2'=z2 as Element of COMPLEX by Def1;
     A1: -z1 = -z1' by Th4;
     A2: -z2 = -z2' by Th4;
     assume A3: z2 <> 0.F_Complex;
     then A4: -z2 <> 0.F_Complex by VECTSP_1:86;
       z1 / z2 = z1' / z2' by A3,Th8;
     hence -(z1 / z2) = -(z1' / z2') by Th4
                    .= (-z1') / z2' by XCMPLX_1:188
                    .= (-z1) / z2 by A1,A3,Th8;
       z1 / z2 = z1' / z2' by A3,Th8;
     hence -(z1 / z2) = -(z1' / z2') by Th4
                    .= z1' / -(z2') by XCMPLX_1:189
                    .= z1 / -z2 by A2,A4,Th8;
    end;

  theorem
     z2 <> 0.F_Complex implies z1 / z2 = (-z1) / (-z2)
    proof
     reconsider z1'=z1,z2'=z2 as Element of COMPLEX by Def1;
     assume A1: z2 <> 0.F_Complex;
     then A2: -z2 <> 0.F_Complex by VECTSP_1:86;
     A3: -z1' = -z1 & -z2' = -z2 by Th4;
     thus z1 / z2 = z1' / z2' by A1,Th8
                 .= (-z1') / (-z2') by XCMPLX_1:192
                 .= (-z1) / (-z2) by A2,A3,Th8;
    end;

  theorem
     z2 <> 0.F_Complex & z4 <> 0.F_Complex implies
    z1 / z2 - z3 / z4 = (z1 * z4 - z3 * z2) / (z2 * z4)
    proof
     reconsider z1'=z1,z2'=z2,z3'=z3,z4'=z4 as Element of COMPLEX by Def1;
     assume A1: z2 <> 0.F_Complex;
     assume A2: z4 <> 0.F_Complex;
     then A3: z1' / z2' = z1 / z2 & z3' / z4' = z3 / z4 by A1,Th8;
     A4: z2' * z4' = z2 * z4 by Th6;
     A5: z2 * z4 <> 0.F_Complex by A1,A2,VECTSP_1:44;
       z1' * z4' = z1 * z4 & z3' * z2' = z3 * z2 by Th6;
     then A6: z1 * z4 - z3 * z2 = z1' * z4' - z3' * z2' by Th5;
     thus z1 / z2 - z3 / z4 = z1' / z2' - z3' / z4' by A3,Th5
            .= (z1' * z4' - z3' * z2') / (z2' * z4') by A1,A2,Th9,XCMPLX_1:131
            .= (z1 * z4 - z3 * z2) / (z2 * z4) by A4,A5,A6,Th8;
    end;

  theorem
     z <> 0.F_Complex implies z1 / z - z2 / z = (z1 - z2) / z
    proof
     reconsider z'=z,z1'=z1,z2'=z2 as Element of COMPLEX by Def1;
     assume A1: z <> 0.F_Complex;
     A2: z1' - z2' = z1 - z2 by Th5;
       z1' / z' = z1 / z & z2' / z' = z2 / z by A1,Th8;
     hence z1 / z - z2 / z = z1' / z' - z2' / z' by Th5
                         .= (z1' - z2') / z' by XCMPLX_1:121
                         .= (z1 - z2) / z by A1,A2,Th8;
    end;

  theorem
     z2 <> 0.F_Complex & (z1 * z2 = z3 or z2 * z1 = z3) implies
    z1 = z3 / z2
    proof
     reconsider z3'=z3,z1'=z1,z2'=z2 as Element of COMPLEX by Def1;
     assume A1: z2 <> 0.F_Complex;
     assume A2: z1 * z2 = z3 or z2 * z1 = z3;
     per cases by A2;
      suppose z1 * z2 = z3;
      then z1' * z2' = z3' by Th6;
      hence z1 = z3' / z2' by A1,Th9,XCMPLX_1:90
              .= z3 / z2 by A1,Th8;
      suppose z2 * z1 = z3;
      then z2' * z1' = z3' by Th6;
      hence z1 = z3' / z2' by A1,Th9,XCMPLX_1:90
              .= z3 / z2 by A1,Th8;
    end;

  theorem
     (the Zero of F_Complex)*' = the Zero of F_Complex
    proof
     consider z be Element of COMPLEX such that
      A1: the Zero of F_Complex = z & (the Zero of F_Complex)*' = z*' by Def2;
       the Zero of F_Complex = 0c by Def1;
     hence thesis by A1,COMPLEX1:113;
    end;

  theorem Th84:
   z*' = the Zero of F_Complex implies z = the Zero of F_Complex
    proof
     assume A1: z*' = the Zero of F_Complex;
     consider z1 be Element of COMPLEX such that
      A2: z1 = z & z1*' = z*' by Def2;
       the Zero of F_Complex = 0c by Def1;
     hence thesis by A1,A2,COMPLEX1:114;
    end;

  theorem
     (the unity of F_Complex)*' = the unity of F_Complex
    proof
     consider z be Element of COMPLEX such that
A1: the unity of F_Complex = z & (the unity of F_Complex)*' = z*' by Def2;
       the unity of F_Complex = 1r by Def1;
     hence thesis by A1,COMPLEX1:115;
    end;

  theorem
     z*'*' = z
    proof
     reconsider z'=z as Element of COMPLEX by Def1;
       z*' = z'*' by Th12;
     hence z*'*' = z'*'*' by Th12
              .= z;
    end;

  theorem
     (z1 + z2)*' = z1*' + z2*'
    proof
     reconsider z1'=z1,z2'=z2 as Element of COMPLEX by Def1;
     A1: z1'*' = z1*' & z2'*' = z2*' by Th12;
       z1' + z2' = z1 + z2 by Th3;
     hence (z1 + z2)*' = (z1' + z2')*' by Th12
                    .= z1'*' + z2'*' by COMPLEX1:118
                    .= z1*' + z2*' by A1,Th3;
    end;

  theorem
     (-z)*' = -(z*')
    proof
     reconsider z'=z as Element of COMPLEX by Def1;
     A1: z'*' = z*' by Th12;
       -z = -z' by Th4;
     hence (-z)*' = (-z')*' by Th12
                .= -(z'*') by COMPLEX1:119
                .= -(z*') by A1,Th4;
    end;

  theorem
     (z1 - z2)*' = z1*' - z2*'
    proof
     reconsider z1'=z1,z2'=z2 as Element of COMPLEX by Def1;
     A1: z1'*' = z1*' & z2'*' = z2*' by Th12;
       z1' - z2' = z1 - z2 by Th5;
     hence (z1 - z2)*' = (z1' - z2')*' by Th12
                    .= z1'*' - z2'*' by COMPLEX1:120
                    .= z1*' - z2*' by A1,Th5;
    end;

  theorem
     (z1 * z2)*' = z1*' * z2*'
    proof
     reconsider z1'=z1,z2'=z2 as Element of COMPLEX by Def1;
     A1: z1'*' = z1*' & z2'*' = z2*' by Th12;
       z1' * z2' = z1 * z2 by Th6;
     hence (z1 * z2)*' = (z1' * z2')*' by Th12
                    .= z1'*' * z2'*' by COMPLEX1:121
                    .= z1*' * z2*' by A1,Th6;
    end;

  theorem
     z <> the Zero of F_Complex implies z"*' = z*'"
    proof
     reconsider z1=z as Element of COMPLEX by Def1;
     assume A1: z <> the Zero of F_Complex;
     then A2: z <> 0.F_Complex by RLVECT_1:def 2;
       z*' <> the Zero of F_Complex by A1,Th84;
     then A3: z*' <> 0.F_Complex by RLVECT_1:def 2;
     A4: z*' = z1*' by Th12;
       z" = z1" by A2,Th7;
     hence z"*' = z1"*' by Th12
             .= z1*'" by COMPLEX1:122
             .= z*'" by A3,A4,Th7;
    end;

  theorem
     z2 <> the Zero of F_Complex implies (z1 / z2)*' = (z1*') / (z2*')
    proof
     reconsider z1'=z1,z2'=z2 as Element of COMPLEX by Def1;
     assume A1: z2 <> the Zero of F_Complex;
     then A2: z2 <> 0.F_Complex by RLVECT_1:def 2;
     A3: z1*' = z1'*' & z2*' = z2'*' by Th12;
       z2*' <> the Zero of F_Complex by A1,Th84;
     then A4: z2*' <> 0.F_Complex by RLVECT_1:def 2;
       z1' / z2' = z1 / z2 by A2,Th8;
     hence (z1 / z2)*' = (z1' / z2')*' by Th12
                    .= (z1'*') / (z2'*') by COMPLEX1:123
                    .= (z1*') / (z2*') by A3,A4,Th8;
    end;

  theorem
     |.the Zero of F_Complex.| = 0
    proof
       the Zero of F_Complex = 0c by Def1;
     hence thesis by Def3,COMPLEX1:130;
    end;

  theorem
     |.z.| = 0 implies z = 0.F_Complex
    proof
     reconsider z'=z as Element of COMPLEX by Def1;
     assume A1: |.z.| = 0;
       |.z'.| = |.z.| by Def3;
     hence z = 0.F_Complex by A1,Th9,COMPLEX1:131;
    end;

  theorem
     0 <= |.z.|
    proof
     reconsider z1=z as Element of COMPLEX by Def1;
       |.z1.| = |.z.| by Def3;
     hence thesis by COMPLEX1:132;
    end;

  theorem
     z <> 0.F_Complex iff 0 < |.z.|
    proof
     reconsider z1=z as Element of COMPLEX by Def1;
     thus z <> 0.F_Complex implies 0 < |.z.|
     proof
      assume z <> 0.F_Complex;
      then 0 < |.z1.| by Th9,COMPLEX1:133;
      hence thesis by Def3;
     end;
     assume 0 < |.z.|;
     then 0 < |.z1.| by Def3;
     hence thesis by Th9,COMPLEX1:133;
    end;

  theorem
     |.the unity of F_Complex.| = 1
    proof
       the unity of F_Complex = 1r by Def1;
     hence |.the unity of F_Complex.| = 1 by Def3,COMPLEX1:134;
    end;

  theorem
     |.-z.| = |.z.|
    proof
     reconsider z1=z as Element of COMPLEX by Def1;
       -z1 = -z by Th4;
     hence |.-z.| = |.-z1.| by Def3
                 .= |.z1.| by COMPLEX1:138
                 .= |.z.| by Def3;
    end;

  theorem
     |.z*'.| = |.z.|
    proof
     reconsider z1=z as Element of COMPLEX by Def1;
       z1*' = z*' by Th12;
     hence |.z*'.| = |.z1*'.| by Def3
                 .= |.z1.| by COMPLEX1:139
                 .= |.z.| by Def3;
    end;

  theorem
     |.z1 + z2.| <= |.z1.| + |.z2.|
    proof
     reconsider z1'=z1,z2'=z2 as Element of COMPLEX by Def1;
       z1' + z2' = z1 + z2 by Th3;
     then A1: |.z1' + z2'.| = |.z1 + z2.| by Def3;
       |.z1'.| = |.z1.| & |.z2'.| = |.z2.| by Def3;
     hence thesis by A1,COMPLEX1:142;
    end;

  theorem
     |.z1 - z2.| <= |.z1.| + |.z2.|
    proof
     reconsider z1'=z1,z2'=z2 as Element of COMPLEX by Def1;
       z1' - z2' = z1 - z2 by Th5;
     then A1: |.z1' - z2'.| = |.z1 - z2.| by Def3;
       |.z1'.| = |.z1.| & |.z2'.| = |.z2.| by Def3;
     hence thesis by A1,COMPLEX1:143;
    end;

  theorem
     |.z1.| - |.z2.| <= |.z1 + z2.|
    proof
     reconsider z1'=z1,z2'=z2 as Element of COMPLEX by Def1;
       z1' + z2' = z1 + z2 by Th3;
     then A1: |.z1' + z2'.| = |.z1 + z2.| by Def3;
       |.z1'.| = |.z1.| & |.z2'.| = |.z2.| by Def3;
     hence thesis by A1,COMPLEX1:144;
    end;

  theorem
     |.z1.| - |.z2.| <= |.z1 - z2.|
    proof
     reconsider z1'=z1,z2'=z2 as Element of COMPLEX by Def1;
       z1' - z2' = z1 - z2 by Th5;
     then A1: |.z1' - z2'.| = |.z1 - z2.| by Def3;
       |.z1'.| = |.z1.| & |.z2'.| = |.z2.| by Def3;
     hence thesis by A1,COMPLEX1:145;
    end;

  theorem
     |.z1 - z2.| = |.z2 - z1.|
    proof
     reconsider z1'=z1,z2'=z2 as Element of COMPLEX by Def1;
     A1: z2' - z1' = z2 - z1 by Th5;
       z1' - z2' = z1 - z2 by Th5;
     hence |.z1 - z2.| = |.z1' - z2'.| by Def3
                        .= |.z2' - z1'.| by COMPLEX1:146
                        .= |.z2 - z1.| by A1,Def3;
    end;

  theorem
     |.z1 - z2.| = 0 iff z1 = z2
    proof
     reconsider z1'=z1,z2'=z2 as Element of COMPLEX by Def1;
     thus |.z1 - z2.| = 0 implies z1 = z2
     proof
      assume A1: |.z1 - z2.| = 0;
        z1 - z2 = z1' - z2' by Th5;
      then |.z1' - z2'.| = 0 by A1,Def3;
      hence z1 = z2 by COMPLEX1:147;
     end;
       z1' - z2' = z1 - z2 by Th5;
     then A2: |.z1' - z2'.| = |.z1 - z2.| by Def3;
     assume z1 = z2;
     hence thesis by A2,COMPLEX1:147;
    end;

  theorem
     z1 <> z2 iff 0 < |.z1 - z2.|
    proof
     reconsider z1'=z1,z2'=z2 as Element of COMPLEX by Def1;
     thus z1 <> z2 implies 0 < |.z1 - z2.|
     proof
      assume A1: z1 <> z2;
        z1 - z2 = z1' - z2' by Th5;
      then |.z1 - z2.| = |.z1' - z2'.| by Def3;
      hence 0 < |.z1 - z2.| by A1,COMPLEX1:148;
     end;
     assume A2: 0 < |.z1 - z2.|;
       z1 - z2 = z1' - z2' by Th5;
     then |.z1 - z2.| = |.z1' - z2'.| by Def3;
     hence z1 <> z2 by A2,COMPLEX1:148;
    end;

  theorem
     |.z1 - z2.| <= |.z1 - z.| + |.z - z2.|
    proof
     reconsider z'=z,z1'=z1,z2'=z2 as Element of COMPLEX by Def1;
       z1' - z2' = z1 - z2 by Th5;
     then A1: |.z1' - z2'.| = |.z1 - z2.| by Def3;
       z1' - z' = z1 - z by Th5;
     then A2: |.z1' - z'.| = |.z1 - z.| by Def3;
       z' - z2' = z - z2 by Th5;
     then |.z' - z2'.| = |.z - z2.| by Def3;
     hence thesis by A1,A2,COMPLEX1:149;
    end;

  theorem
     abs(|.z1.| - |.z2.|) <= |.z1 - z2.|
    proof
     reconsider z1'=z1,z2'=z2 as Element of COMPLEX by Def1;
     A1: |.z1'.| = |.z1.| & |.z2'.| = |.z2.| by Def3;
       z1' - z2' = z1 - z2 by Th5;
     then |.z1' - z2'.| = |.z1 - z2.| by Def3;
     hence thesis by A1,COMPLEX1:150;
    end;

  theorem
     |.z1*z2.| = |.z1.|*|.z2.|
    proof
     reconsider z1'=z1,z2'=z2 as Element of COMPLEX by Def1;
     A1: |.z1'.| = |.z1.| & |.z2'.| = |.z2.| by Def3;
       z1' * z2' = z1 * z2 by Th6;
     hence |.z1 * z2.| = |.z1' * z2'.| by Def3
                      .= |.z1.| * |.z2.| by A1,COMPLEX1:151;
    end;

  theorem
     z <> the Zero of F_Complex implies |.z".| = |.z.|"
    proof
     reconsider z1=z as Element of COMPLEX by Def1;
     assume A1: z <> the Zero of F_Complex;
     then A2: z <> 0c by Def1;
       z <> 0.F_Complex by A1,Def1,Th9;
     then z" = z1" by Th7;
     hence |.z".| = |.z1".| by Def3
                 .= |.z1.|" by A2,COMPLEX1:152
                 .= |.z.|" by Def3;
    end;

  theorem
     z2 <> the Zero of F_Complex implies |.z1.| / |.z2.| = |.z1 / z2.|
    proof
     reconsider z1'=z1,z2'=z2 as Element of COMPLEX by Def1;
     assume A1: z2 <> the Zero of F_Complex;
     then A2: z2 <> 0c by Def1;
       z2 <> 0.F_Complex by A1,Def1,Th9;
     then A3: z1' / z2' = z1 / z2 by Th8;
       |.z1'.| = |.z1.| & |.z2'.| = |.z2.| by Def3;
     hence |.z1.| / |.z2.| = |.z1' / z2'.| by A2,COMPLEX1:153
                          .= |.z1 / z2.| by A3,Def3;
    end;

  theorem
     |.z * z.| = |.z * z*'.|
    proof
     reconsider z1=z as Element of COMPLEX by Def1;
       z1*' = z*' by Th12;
     then A1: z1 * z1*' = z * z*' by Th6;
       z1 * z1 = z * z by Th6;
     hence |.z * z.| = |.z1 * z1.| by Def3
                    .= |.z1 * z1*'.| by COMPLEX1:155
                    .= |.z * z*'.| by A1,Def3;
    end;

Back to top