Description: The relation "is isomorphic to" for (unital) rings. (Contributed by AV, 24-Dec-2019)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | brric | |- ( R ~=r S <-> ( R RingIso S ) =/= (/) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | df-ric | |- ~=r = ( `' RingIso " ( _V \ 1o ) ) |
|
| 2 | rimfn | |- RingIso Fn ( _V X. _V ) |
|
| 3 | 1 2 | brwitnlem | |- ( R ~=r S <-> ( R RingIso S ) =/= (/) ) |