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Mirrors > Home > MPE Home > Th. List > con2bii | Structured version Visualization version GIF version |
Description: A contraposition inference. (Contributed by NM, 12-Mar-1993.) |
Ref | Expression |
---|---|
con2bii.1 | ⊢ (𝜑 ↔ ¬ 𝜓) |
Ref | Expression |
---|---|
con2bii | ⊢ (𝜓 ↔ ¬ 𝜑) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | notnotb 318 | . 2 ⊢ (𝜓 ↔ ¬ ¬ 𝜓) | |
2 | con2bii.1 | . 2 ⊢ (𝜑 ↔ ¬ 𝜓) | |
3 | 1, 2 | xchbinxr 338 | 1 ⊢ (𝜓 ↔ ¬ 𝜑) |
Colors of variables: wff setvar class |
Syntax hints: ¬ wn 3 ↔ wb 209 |
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 210 |
This theorem is referenced by: xor3 387 imnan 403 annim 407 pm4.53 983 pm4.55 985 oran 987 nanan 1484 xnor 1504 xorneg 1515 noror 1529 alnex 1783 exnal 1828 exnalimn 1845 2exnexn 1847 equs3OLD 1965 19.3vOLD 1989 nne 2991 rexnal 3201 dfrex2 3202 r2exlem 3261 ddif 4064 dfun2 4186 dfin2 4187 difin 4188 disj4 4366 snnzb 4614 onuninsuci 7535 omopthi 8267 dfsup2 8892 rankxplim3 9294 alephgeom 9493 fin1a2lem7 9817 fin41 9855 reclem2pr 10459 1re 10630 ltnlei 10750 divalglem8 15741 f1omvdco3 18569 elcls 21678 ist1-2 21952 fin1aufil 22537 dchrelbas3 25822 tgdim01 26301 axcontlem12 26769 avril1 28248 creq0 30497 dftr6 33099 sltval2 33276 sltres 33282 nosepeq 33302 nolt02o 33312 nosupbnd2lem1 33328 dfon3 33466 dffun10 33488 brub 33528 bj-bixor 34038 bj-modal4e 34162 con2bii2 34750 wl-dfrexex 35015 wl-dfrexsb 35016 heiborlem1 35249 heiborlem6 35254 heiborlem8 35256 cdleme0nex 37586 wopprc 39971 1nevenALTV 44209 |
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