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Mirrors > Home > ILE Home > Th. List > fal | Unicode version |
Description: The truth value is refutable. (Contributed by Anthony Hart, 22-Oct-2010.) (Proof shortened by Mel L. O'Cat, 11-Mar-2012.) |
Ref | Expression |
---|---|
fal |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | tru 1247 | . . 3 | |
2 | 1 | notnoti 574 | . 2 |
3 | df-fal 1249 | . 2 | |
4 | 2, 3 | mtbir 596 | 1 |
Colors of variables: wff set class |
Syntax hints: wn 3 wtru 1244 wfal 1248 |
This theorem was proved from axioms: ax-1 5 ax-2 6 ax-mp 7 ax-ia1 99 ax-ia2 100 ax-ia3 101 ax-in1 544 ax-in2 545 |
This theorem depends on definitions: df-bi 110 df-tru 1246 df-fal 1249 |
This theorem is referenced by: nbfal 1254 bifal 1256 falim 1257 dfnot 1262 notfal 1305 alnex 1388 csbprc 3262 bdnth 9954 |
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