let F be Field; :: thesis: for E1 being FieldExtension of F
for E2 being b1 -homomorphic FieldExtension of F
for h being Homomorphism of E1,E2 holds
( h is F -fixing iff h is linear-transformation of (VecSp (E1,F)),(VecSp (E2,F)) )

let E1 be FieldExtension of F; :: thesis: for E2 being E1 -homomorphic FieldExtension of F
for h being Homomorphism of E1,E2 holds
( h is F -fixing iff h is linear-transformation of (VecSp (E1,F)),(VecSp (E2,F)) )

let E2 be E1 -homomorphic FieldExtension of F; :: thesis: for h being Homomorphism of E1,E2 holds
( h is F -fixing iff h is linear-transformation of (VecSp (E1,F)),(VecSp (E2,F)) )

let h be Homomorphism of E1,E2; :: thesis: ( h is F -fixing iff h is linear-transformation of (VecSp (E1,F)),(VecSp (E2,F)) )
G: now :: thesis: ( h is F -fixing implies h is linear-transformation of (VecSp (E1,F)),(VecSp (E2,F)) )
assume AS: h is F -fixing ; :: thesis: h is linear-transformation of (VecSp (E1,F)),(VecSp (E2,F))
H: dom h = the carrier of E1 by FUNCT_2:def 1
.= the carrier of (VecSp (E1,F)) by FIELD_4:def 6 ;
rng h c= the carrier of E2 by RELAT_1:def 19;
then rng h c= the carrier of (VecSp (E2,F)) by FIELD_4:def 6;
then reconsider f = h as Function of (VecSp (E1,F)),(VecSp (E2,F)) by H, FUNCT_2:2;
now :: thesis: for x, y being Element of (VecSp (E1,F)) holds f . (x + y) = (f . x) + (f . y)
let x, y be Element of (VecSp (E1,F)); :: thesis: f . (x + y) = (f . x) + (f . y)
reconsider a = x, b = y as Element of E1 by FIELD_4:def 6;
H: x + y = a + b by FIELD_4:def 6;
thus f . (x + y) = (h . a) + (h . b) by H, VECTSP_1:def 20
.= (f . x) + (f . y) by FIELD_4:def 6 ; :: thesis: verum
end;
then A: f is additive ;
now :: thesis: for a being Scalar of F
for x being Vector of (VecSp (E1,F)) holds f . (a * x) = a * (f . x)
let a be Scalar of F; :: thesis: for x being Vector of (VecSp (E1,F)) holds f . (a * x) = a * (f . x)
let x be Vector of (VecSp (E1,F)); :: thesis: f . (a * x) = a * (f . x)
reconsider v = x as Element of E1 by FIELD_4:def 6;
F is Subring of E1 by FIELD_4:def 1;
then the carrier of F c= the carrier of E1 by C0SP1:def 3;
then reconsider u1 = a as Element of E1 ;
F is Subring of E2 by FIELD_4:def 1;
then the carrier of F c= the carrier of E2 by C0SP1:def 3;
then reconsider u2 = a as Element of E2 ;
I: [u1,v] in [: the carrier of F, the carrier of E1:] by ZFMISC_1:def 2;
H: a * x = ( the multF of E1 | [: the carrier of F, the carrier of E1:]) . (u1,v) by FIELD_4:def 6
.= u1 * v by I, FUNCT_1:49 ;
J: [u2,(h . v)] in [: the carrier of F, the carrier of E2:] by ZFMISC_1:def 2;
thus f . (a * x) = (h . u1) * (h . v) by H, GROUP_6:def 6
.= u2 * (h . v) by AS
.= ( the multF of E2 | [: the carrier of F, the carrier of E2:]) . (u2,(h . v)) by J, FUNCT_1:49
.= a * (f . x) by FIELD_4:def 6 ; :: thesis: verum
end;
hence h is linear-transformation of (VecSp (E1,F)),(VecSp (E2,F)) by A, MOD_2:def 2; :: thesis: verum
end;
set V1 = VecSp (E1,F);
set V2 = VecSp (E2,F);
now :: thesis: ( h is linear-transformation of (VecSp (E1,F)),(VecSp (E2,F)) implies h is F -fixing )
assume h is linear-transformation of (VecSp (E1,F)),(VecSp (E2,F)) ; :: thesis: h is F -fixing
then reconsider h1 = h as linear-transformation of (VecSp (E1,F)),(VecSp (E2,F)) ;
A: the carrier of E1 = the carrier of (VecSp (E1,F)) by FIELD_4:def 6;
reconsider 1V = 1. E1 as Element of (VecSp (E1,F)) by FIELD_4:def 6;
now :: thesis: for a being Element of F holds h . a = a
let a be Element of F; :: thesis: h . a = a
F is Subfield of E1 by FIELD_4:7;
then B: ( the carrier of F c= the carrier of E1 & the multF of F = the multF of E1 || the carrier of F & 1. F = 1. E1 ) by EC_PF_1:def 1;
F is Subfield of E2 by FIELD_4:7;
then the carrier of F c= the carrier of E2 by EC_PF_1:def 1;
then reconsider a2 = a as Element of E2 ;
reconsider aV = a as Element of (VecSp (E1,F)) by A, B;
D: [a,(1. F)] in [: the carrier of F, the carrier of E1:] by B, ZFMISC_1:def 2;
E: [a,(1. F)] in [: the carrier of F, the carrier of F:] by ZFMISC_1:def 2;
F: the multF of F . (a,(1. F)) = the multF of E1 . (a,(1. F)) by B, E, FUNCT_1:49
.= ( the multF of E1 | [: the carrier of F, the carrier of E1:]) . (a,(1. F)) by D, FUNCT_1:49
.= the lmult of (VecSp (E1,F)) . (a,1V) by B, FIELD_4:def 6 ;
I: [a,(1. E2)] in [: the carrier of F, the carrier of E2:] by ZFMISC_1:def 2;
G: h1 . 1V = h . (1_ E1)
.= 1_ E2 by GROUP_1:def 13 ;
J: the lmult of (VecSp (E2,F)) . (a,(1. E2)) = ( the multF of E2 | [: the carrier of F, the carrier of E2:]) . (a,(1. E2)) by FIELD_4:def 6
.= the multF of E2 . (a2,(1. E2)) by I, FUNCT_1:49 ;
h . (a * (1. F)) = h1 . (a * 1V) by F
.= a * (h1 . 1V) by MOD_2:def 2
.= a2 * (1. E2) by J, G ;
hence h . a = a ; :: thesis: verum
end;
hence h is F -fixing ; :: thesis: verum
end;
hence ( h is F -fixing iff h is linear-transformation of (VecSp (E1,F)),(VecSp (E2,F)) ) by G; :: thesis: verum