Metamath Proof Explorer


Theorem reneg0addid2

Description: Negative zero is a left additive identity. (Contributed by Steven Nguyen, 7-Jan-2023)

Ref Expression
Assertion reneg0addid2 A 0 - 0 + A = A

Proof

Step Hyp Ref Expression
1 elre0re A 0
2 rernegcl 0 0 - 0
3 elre0re 0 0
4 renegid 0 0 + 0 - 0 = 0
5 2 3 4 readdid1addid2d 0 A 0 - 0 + A = A
6 1 5 mpancom A 0 - 0 + A = A