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Mirrors > Home > ILE Home > Th. List > biid | Unicode version |
Description: Principle of identity for logical equivalence. Theorem *4.2 of [WhiteheadRussell] p. 117. (Contributed by NM, 5-Aug-1993.) |
Ref | Expression |
---|---|
biid |
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Step | Hyp | Ref | Expression |
---|---|---|---|
1 | id 19 |
. 2
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2 | 1, 1 | impbii 125 |
1
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Colors of variables: wff set class |
Syntax hints: ![]() |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-ia2 106 ax-ia3 107 |
This theorem depends on definitions: df-bi 116 |
This theorem is referenced by: biidd 171 3anbi1i 1173 3anbi2i 1174 3anbi3i 1175 trubitru 1394 falbifal 1397 eqid 2140 abid2 2261 abid2f 2307 ceqsexg 2817 nnwetri 6812 fsum2d 11236 isstructim 12012 |
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