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Related theorems Unicode version |
| Description: All set variables are sets (see isset 1860). Theorem 6.8 of [Quine] p. 43. |
| Ref | Expression |
|---|---|
| visset |
|
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | eqid 1518 |
. 2
| |
| 2 | df-v 1858 |
. . 3
| |
| 3 | 2 | abeq2i 1613 |
. 2
|
| 4 | 1, 3 | mpbir 188 |
1
|