The Mizar article:

The Concept of Fuzzy Relation and Basic Properties of its Operation

by
Takashi Mitsuishi,
Katsumi Wasaki, and
Yasunari Shidama

Received September 15, 2000

Copyright (c) 2000 Association of Mizar Users

MML identifier: FUZZY_3
[ MML identifier index ]


environ

 vocabulary RELAT_1, FUNCT_3, FUNCT_1, SQUARE_1, FUZZY_1, BOOLE, FUZZY_3,
      FUNCT_2;
 notation XBOOLE_0, ZFMISC_1, SUBSET_1, XREAL_0, RELSET_1, FUNCT_2, RFUNCT_1,
      FUZZY_1;
 constructors SEQ_1, RFUNCT_1, FUZZY_2, RCOMP_1, XCMPLX_0, MEMBERED;
 clusters SUBSET_1, MEMBERED;
 theorems FUZZY_1, FUNCT_2, FUZZY_2;

begin

 reserve C1,C2 for non empty set;

definition let C be non empty set;
 cluster -> quasi_total Membership_Func of C;
 coherence
  proof let f be Membership_Func of C;
      dom f = C by FUZZY_1:def 1;
   hence thesis by FUNCT_2:def 1;
  end;
end;

definition let C1,C2 be non empty set;
  mode RMembership_Func of C1,C2 is Membership_Func of [:C1,C2:];
end;

definition let C1,C2 be non empty set;
           let h be RMembership_Func of C1,C2;
  mode FuzzyRelation of C1,C2,h is FuzzySet of [:C1,C2:],h;
end;

 reserve f,g for RMembership_Func of C1,C2;

begin :: Empty Fuzzy Set and Universal Fuzzy Set

definition let C1,C2 be non empty set;
  mode Zero_Relation of C1,C2 is Empty_FuzzySet of [:C1,C2:];
  mode Universe_Relation of C1,C2 is Universal_FuzzySet of [:C1,C2:];
end;

 reserve X for Universe_Relation of C1,C2;
 reserve O for Zero_Relation of C1,C2;

definition
  let C1,C2 be non empty set;
  func Zmf(C1,C2) -> RMembership_Func of C1,C2 equals :Def1:
  chi({},[:C1,C2:]);
  correctness by FUZZY_1:23;

  func Umf(C1,C2) -> RMembership_Func of C1,C2 equals :Def2:
  chi([:C1,C2:],[:C1,C2:]);
  correctness by FUZZY_1:2;
end;

canceled 44;

theorem Th45: Zmf(C1,C2) = EMF [:C1,C2:]
 proof
  thus Zmf(C1,C2) = chi({},[:C1,C2:]) by Def1
    .= EMF [:C1,C2:] by FUZZY_1:def 13;
 end;

theorem Th46: Umf(C1,C2) = UMF [:C1,C2:]
 proof
  thus Umf(C1,C2) = chi([:C1,C2:],[:C1,C2:]) by Def2
    .= UMF [:C1,C2:] by FUZZY_1:def 14;
 end;

theorem
  O is FuzzyRelation of C1,C2,Zmf(C1,C2) by Th45;

theorem
  X is FuzzyRelation of C1,C2,Umf(C1,C2) by Th46;

canceled 3;

theorem
  for x be Element of [:C1,C2:],h be RMembership_Func of C1,C2 holds
(Zmf(C1,C2)).x <= h.x & h.x <= (Umf(C1,C2)).x
proof
    Zmf(C1,C2) = EMF [:C1,C2:] & Umf(C1,C2) = UMF [:C1,C2:] by Th45,Th46;
 hence thesis by FUZZY_1:31;
end;

theorem
  max(f,Umf(C1,C2)) = Umf(C1,C2) & min(f,Umf(C1,C2)) = f &
max(f,Zmf(C1,C2)) = f & min(f,Zmf(C1,C2)) = Zmf(C1,C2)
proof
    Zmf(C1,C2) = EMF [:C1,C2:] & Umf(C1,C2) = UMF [:C1,C2:] by Th45,Th46;
 hence thesis by FUZZY_1:32;
end;

canceled 7;

theorem
  1_minus(Zmf(C1,C2)) = Umf(C1,C2) & 1_minus(Umf(C1,C2)) = Zmf(C1,C2)
proof
    Zmf(C1,C2) = EMF [:C1,C2:] & Umf(C1,C2) = UMF [:C1,C2:] by Th45,Th46;
 hence thesis by FUZZY_1:62;
end;

canceled 59;

theorem
  min(f,1_minus g) = Zmf(C1,C2) implies
for c being Element of [:C1,C2:] holds f.c <= g.c
 proof Zmf(C1,C2) = EMF [:C1,C2:] by Th45;
  hence thesis by FUZZY_2:59;
 end;

canceled;

theorem
  min(f,g) = Zmf(C1,C2) implies min(f,1_minus g) = f
proof Zmf(C1,C2) = EMF [:C1,C2:] by Th45;
  hence thesis by FUZZY_2:61;
end;

Back to top