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Mirrors > Home > NFE Home > Th. List > con4bii | Unicode version |
Description: A contraposition inference. (Contributed by NM, 21-May-1994.) |
Ref | Expression |
---|---|
con4bii.1 |
Ref | Expression |
---|---|
con4bii |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | con4bii.1 | . 2 | |
2 | notbi 286 | . 2 | |
3 | 1, 2 | mpbir 200 | 1 |
Colors of variables: wff setvar class |
Syntax hints: wn 3 wb 176 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 |
This theorem depends on definitions: df-bi 177 |
This theorem is referenced by: 2false 339 19.35 1600 2ralor 2780 gencbval 2903 eq0 3564 ab0 3569 uni0b 3916 |
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