Metamath Proof Explorer


Theorem subsid1

Description: Identity law for subtraction. (Contributed by Scott Fenton, 3-Feb-2025)

Ref Expression
Assertion subsid1 Could not format assertion : No typesetting found for |- ( A e. No -> ( A -s 0s ) = A ) with typecode |-

Proof

Step Hyp Ref Expression
1 0sno Could not format 0s e. No : No typesetting found for |- 0s e. No with typecode |-
2 subsval Could not format ( ( A e. No /\ 0s e. No ) -> ( A -s 0s ) = ( A +s ( -us ` 0s ) ) ) : No typesetting found for |- ( ( A e. No /\ 0s e. No ) -> ( A -s 0s ) = ( A +s ( -us ` 0s ) ) ) with typecode |-
3 1 2 mpan2 Could not format ( A e. No -> ( A -s 0s ) = ( A +s ( -us ` 0s ) ) ) : No typesetting found for |- ( A e. No -> ( A -s 0s ) = ( A +s ( -us ` 0s ) ) ) with typecode |-
4 negs0s Could not format ( -us ` 0s ) = 0s : No typesetting found for |- ( -us ` 0s ) = 0s with typecode |-
5 4 oveq2i Could not format ( A +s ( -us ` 0s ) ) = ( A +s 0s ) : No typesetting found for |- ( A +s ( -us ` 0s ) ) = ( A +s 0s ) with typecode |-
6 addsrid Could not format ( A e. No -> ( A +s 0s ) = A ) : No typesetting found for |- ( A e. No -> ( A +s 0s ) = A ) with typecode |-
7 5 6 eqtrid Could not format ( A e. No -> ( A +s ( -us ` 0s ) ) = A ) : No typesetting found for |- ( A e. No -> ( A +s ( -us ` 0s ) ) = A ) with typecode |-
8 3 7 eqtrd Could not format ( A e. No -> ( A -s 0s ) = A ) : No typesetting found for |- ( A e. No -> ( A -s 0s ) = A ) with typecode |-