Metamath Proof Explorer


Theorem rngogrphom

Description: A ring homomorphism is a group homomorphism. (Contributed by Jeff Madsen, 2-Jan-2011)

Ref Expression
Hypotheses rnggrphom.1 G=1stR
rnggrphom.2 J=1stS
Assertion rngogrphom RRingOpsSRingOpsFRRngHomSFGGrpOpHomJ

Proof

Step Hyp Ref Expression
1 rnggrphom.1 G=1stR
2 rnggrphom.2 J=1stS
3 eqid ranG=ranG
4 eqid ranJ=ranJ
5 1 3 2 4 rngohomf RRingOpsSRingOpsFRRngHomSF:ranGranJ
6 1 3 2 rngohomadd RRingOpsSRingOpsFRRngHomSxranGyranGFxGy=FxJFy
7 6 eqcomd RRingOpsSRingOpsFRRngHomSxranGyranGFxJFy=FxGy
8 7 ralrimivva RRingOpsSRingOpsFRRngHomSxranGyranGFxJFy=FxGy
9 1 rngogrpo RRingOpsGGrpOp
10 2 rngogrpo SRingOpsJGrpOp
11 3 4 elghomOLD GGrpOpJGrpOpFGGrpOpHomJF:ranGranJxranGyranGFxJFy=FxGy
12 9 10 11 syl2an RRingOpsSRingOpsFGGrpOpHomJF:ranGranJxranGyranGFxJFy=FxGy
13 12 3adant3 RRingOpsSRingOpsFRRngHomSFGGrpOpHomJF:ranGranJxranGyranGFxJFy=FxGy
14 5 8 13 mpbir2and RRingOpsSRingOpsFRRngHomSFGGrpOpHomJ