Metamath Proof Explorer


Theorem mulridd

Description: Identity law for multiplication. (Contributed by Mario Carneiro, 27-May-2016)

Ref Expression
Hypothesis addcld.1 φA
Assertion mulridd φA1=A

Proof

Step Hyp Ref Expression
1 addcld.1 φA
2 mulrid AA1=A
3 1 2 syl φA1=A