Description: Obsolete version of snelpwi as of 17-Jan-2025. (Contributed by NM, 28-May-1995) (Proof modification is discouraged.) (New usage is discouraged.)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | snelpwiOLD | |- ( A e. B -> { A } e. ~P B ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | snssi | |- ( A e. B -> { A } C_ B ) |
|
| 2 | snex | |- { A } e. _V |
|
| 3 | 2 | elpw | |- ( { A } e. ~P B <-> { A } C_ B ) |
| 4 | 1 3 | sylibr | |- ( A e. B -> { A } e. ~P B ) |