Theorem opprbasOLD

Description: Obsolete version of opprbas as of 6-Nov-2024. Base set of an opposite ring. (Contributed by Mario Carneiro, 1-Dec-2014) (New usage is discouraged.) (Proof modification is discouraged.)

	Ref	Expression
Hypotheses	opprbas.1	|- O = ( oppR ` R )
	opprbas.2	|- B = ( Base ` R )
Assertion	opprbasOLD	|- B = ( Base ` O )

Proof

Step	Hyp	Ref	Expression
1		opprbas.1	|- O = ( oppR ` R )
2		opprbas.2	|- B = ( Base ` R )
3		df-base	|- Base = Slot 1
4		1nn	|- 1 e. NN
5		1lt3	|- 1 < 3
6	1 3 4 5	opprlemOLD	|- ( Base ` R ) = ( Base ` O )
7	2 6	eqtri	|- B = ( Base ` O )