Metamath Proof Explorer


Theorem pncan1

Description: Cancellation law for addition and subtraction with 1. (Contributed by Alexander van der Vekens, 3-Oct-2018)

Ref Expression
Assertion pncan1 AA+1-1=A

Proof

Step Hyp Ref Expression
1 id AA
2 1cnd A1
3 1 2 pncand AA+1-1=A