let R be gcdDomain; for Amp being AmpleSet of R
for a, b, c being Element of R st c divides gcd a,b,Amp holds
( c divides a & c divides b )
let Amp be AmpleSet of R; for a, b, c being Element of R st c divides gcd a,b,Amp holds
( c divides a & c divides b )
let A, B, C be Element of R; ( C divides gcd A,B,Amp implies ( C divides A & C divides B ) )
assume
C divides gcd A,B,Amp
; ( C divides A & C divides B )
then consider D being Element of R such that
A1:
C * D = gcd A,B,Amp
by Def1;
gcd A,B,Amp divides A
by Def12;
then consider E being Element of R such that
A2:
(gcd A,B,Amp) * E = A
by Def1;
A3:
C * (D * E) = A
by A1, A2, GROUP_1:def 4;
gcd A,B,Amp divides B
by Def12;
then consider E being Element of R such that
A4:
(gcd A,B,Amp) * E = B
by Def1;
C * (D * E) = B
by A1, A4, GROUP_1:def 4;
hence
( C divides A & C divides B )
by A3, Def1; verum