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Mirrors > Home > ILE Home > Th. List > trubitru | GIF version |
Description: A ↔ identity. (Contributed by Anthony Hart, 22-Oct-2010.) (Proof shortened by Andrew Salmon, 13-May-2011.) |
Ref | Expression |
---|---|
trubitru | ⊢ ((⊤ ↔ ⊤) ↔ ⊤) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | biid 171 | . 2 ⊢ (⊤ ↔ ⊤) | |
2 | 1 | bitru 1365 | 1 ⊢ ((⊤ ↔ ⊤) ↔ ⊤) |
Colors of variables: wff set class |
Syntax hints: ↔ wb 105 ⊤wtru 1354 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-ia1 106 ax-ia2 107 ax-ia3 108 |
This theorem depends on definitions: df-bi 117 df-tru 1356 |
This theorem is referenced by: (None) |
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