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Mirrors > Home > ILE Home > Th. List > orcom | GIF version |
Description: Commutative law for disjunction. Theorem *4.31 of [WhiteheadRussell] p. 118. (Contributed by NM, 5-Aug-1993.) (Proof shortened by Wolf Lammen, 15-Nov-2012.) |
Ref | Expression |
---|---|
orcom | ⊢ ((𝜑 ∨ 𝜓) ↔ (𝜓 ∨ 𝜑)) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | pm1.4 716 | . 2 ⊢ ((𝜑 ∨ 𝜓) → (𝜓 ∨ 𝜑)) | |
2 | pm1.4 716 | . 2 ⊢ ((𝜓 ∨ 𝜑) → (𝜑 ∨ 𝜓)) | |
3 | 1, 2 | impbii 125 | 1 ⊢ ((𝜑 ∨ 𝜓) ↔ (𝜓 ∨ 𝜑)) |
Colors of variables: wff set class |
Syntax hints: ↔ wb 104 ∨ wo 697 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-ia1 105 ax-ia2 106 ax-ia3 107 ax-io 698 |
This theorem depends on definitions: df-bi 116 |
This theorem is referenced by: orcomd 718 orbi1i 752 orass 756 or32 759 or42 761 orbi1d 780 pm5.61 783 oranabs 804 ordir 806 pm2.1dc 822 notnotrdc 828 dcnnOLD 834 pm5.17dc 889 pm5.7dc 938 dn1dc 944 pm5.75 946 3orrot 968 3orcomb 971 excxor 1356 xorcom 1366 19.33b2 1608 nf4dc 1648 nf4r 1649 19.31r 1659 dveeq2 1787 sbequilem 1810 dvelimALT 1983 dvelimfv 1984 dvelimor 1991 eueq2dc 2852 uncom 3215 reuun2 3354 prel12 3693 exmid01 4116 exmidsssnc 4121 ordtriexmid 4432 ordtri2orexmid 4433 ontr2exmid 4435 onsucsssucexmid 4437 ordsoexmid 4472 ordtri2or2exmid 4481 cnvsom 5077 fununi 5186 frec0g 6287 frecabcl 6289 frecsuclem 6296 swoer 6450 inffiexmid 6793 enq0tr 7235 letr 7840 reapmul1 8350 reapneg 8352 reapcotr 8353 remulext1 8354 apsym 8361 mulext1 8367 elznn0nn 9061 elznn0 9062 zapne 9118 nneoor 9146 nn01to3 9402 ltxr 9555 xrletr 9584 maxclpr 10987 minclpr 11001 odd2np1lem 11558 lcmcom 11734 dvdsprime 11792 coprm 11811 bdbl 12661 subctctexmid 13185 |
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