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Mirrors > Home > MPE Home > Th. List > fal | Structured version Visualization version GIF 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 1479 | . . 3 ⊢ ⊤ | |
2 | 1 | notnoti 136 | . 2 ⊢ ¬ ¬ ⊤ |
3 | df-fal 1481 | . 2 ⊢ (⊥ ↔ ¬ ⊤) | |
4 | 2, 3 | mtbir 312 | 1 ⊢ ¬ ⊥ |
Colors of variables: wff setvar class |
Syntax hints: ¬ wn 3 ⊤wtru 1476 ⊥wfal 1480 |
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 196 df-tru 1478 df-fal 1481 |
This theorem is referenced by: nbfal 1486 bifal 1488 falim 1489 dfnot 1493 falantru 1499 notfal 1510 nffal 1723 nonconne 2794 csbprc 3932 csbprcOLD 3933 axnulALT 4715 axnul 4716 canthp1 9355 rlimno1 14232 1stccnp 21075 rusgra0edg 26482 alnof 31571 nextf 31575 negsym1 31586 nandsym1 31591 subsym1 31596 bj-falor 31742 bj-nffal 31775 orfa 33051 fald 33106 dihglblem6 35647 ifpdfan 36829 ifpnot 36833 ifpid2 36834 ifpdfxor 36851 |
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