Metamath Proof Explorer


Theorem npcan1

Description: Cancellation law for subtraction and addition with 1. (Contributed by Alexander van der Vekens, 5-Oct-2018)

Ref Expression
Assertion npcan1 AA-1+1=A

Proof

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