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Mirrors > Home > MPE Home > Th. List > Mathboxes > bj-equsvt | Structured version Visualization version GIF version |
Description: A variant of equsv 2012. (Contributed by BJ, 7-Oct-2024.) |
Ref | Expression |
---|---|
bj-equsvt | ⊢ (Ⅎ'𝑥𝜑 → (∀𝑥(𝑥 = 𝑦 → 𝜑) ↔ 𝜑)) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | bj-19.23t 34638 | . 2 ⊢ (Ⅎ'𝑥𝜑 → (∀𝑥(𝑥 = 𝑦 → 𝜑) ↔ (∃𝑥 𝑥 = 𝑦 → 𝜑))) | |
2 | ax6ev 1978 | . . 3 ⊢ ∃𝑥 𝑥 = 𝑦 | |
3 | 2 | a1bi 366 | . 2 ⊢ (𝜑 ↔ (∃𝑥 𝑥 = 𝑦 → 𝜑)) |
4 | 1, 3 | bitr4di 292 | 1 ⊢ (Ⅎ'𝑥𝜑 → (∀𝑥(𝑥 = 𝑦 → 𝜑) ↔ 𝜑)) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ↔ wb 209 ∀wal 1541 ∃wex 1787 Ⅎ'wnnf 34591 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1803 ax-4 1817 ax-6 1976 |
This theorem depends on definitions: df-bi 210 df-an 400 df-ex 1788 df-bj-nnf 34592 |
This theorem is referenced by: bj-equsalvwd 34648 |
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