Metamath Proof Explorer


Theorem cnvcnvssOLD

Description: Obsolete version of cnvcnvss as of 10-Jun-2026. (Contributed by NM, 23-Jul-2004) (Proof modification is discouraged.) (New usage is discouraged.)

Ref Expression
Assertion cnvcnvssOLD A -1 -1 A

Proof

Step Hyp Ref Expression
1 cnvcnv A -1 -1 = A V × V
2 inss1 A V × V A
3 1 2 eqsstri A -1 -1 A