Metamath Proof Explorer


Theorem opprbas

Description: Base set of an opposite ring. (Contributed by Mario Carneiro, 1-Dec-2014) (Proof shortened by AV, 6-Nov-2024)

Ref Expression
Hypotheses opprbas.1 O = opp r R
opprbas.2 B = Base R
Assertion opprbas B = Base O

Proof

Step Hyp Ref Expression
1 opprbas.1 O = opp r R
2 opprbas.2 B = Base R
3 baseid Base = Slot Base ndx
4 basendxnmulrndx Base ndx ndx
5 1 3 4 opprlem Base R = Base O
6 2 5 eqtri B = Base O