This is an inofficial mirror of http://metamath.tirix.org for personal testing of a visualizer extension only.
Description: Obsolete version of csbcnv as of 4-Jun-2026. (Contributed by Thierry Arnoux, 8-Feb-2017) (Revised by NM, 23-Aug-2018) (Proof modification is discouraged.) (New usage is discouraged.)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | csbcnvOLD |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | sbcbr | ||
| 2 | 1 | opabbii | |
| 3 | csbopab | ||
| 4 | df-cnv | ||
| 5 | 2 3 4 | 3eqtr4ri | |
| 6 | df-cnv | ||
| 7 | 6 | csbeq2i | |
| 8 | 5 7 | eqtr4i |