Intuitionistic Logic Explorer |
< Previous
Next >
Nearby theorems |
||
Mirrors > Home > ILE Home > Th. List > iftrue | GIF version |
Description: Value of the conditional operator when its first argument is true. (Contributed by NM, 15-May-1999.) (Proof shortened by Andrew Salmon, 26-Jun-2011.) |
Ref | Expression |
---|---|
iftrue | ⊢ (𝜑 → if(𝜑, 𝐴, 𝐵) = 𝐴) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | dedlema 953 | . . 3 ⊢ (𝜑 → (𝑥 ∈ 𝐴 ↔ ((𝑥 ∈ 𝐴 ∧ 𝜑) ∨ (𝑥 ∈ 𝐵 ∧ ¬ 𝜑)))) | |
2 | 1 | abbi2dv 2258 | . 2 ⊢ (𝜑 → 𝐴 = {𝑥 ∣ ((𝑥 ∈ 𝐴 ∧ 𝜑) ∨ (𝑥 ∈ 𝐵 ∧ ¬ 𝜑))}) |
3 | df-if 3475 | . 2 ⊢ if(𝜑, 𝐴, 𝐵) = {𝑥 ∣ ((𝑥 ∈ 𝐴 ∧ 𝜑) ∨ (𝑥 ∈ 𝐵 ∧ ¬ 𝜑))} | |
4 | 2, 3 | syl6reqr 2191 | 1 ⊢ (𝜑 → if(𝜑, 𝐴, 𝐵) = 𝐴) |
Colors of variables: wff set class |
Syntax hints: ¬ wn 3 → wi 4 ∧ wa 103 ∨ wo 697 = wceq 1331 ∈ wcel 1480 {cab 2125 ifcif 3474 |
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-in2 604 ax-io 698 ax-5 1423 ax-7 1424 ax-gen 1425 ax-ie1 1469 ax-ie2 1470 ax-8 1482 ax-11 1484 ax-4 1487 ax-17 1506 ax-i9 1510 ax-ial 1514 ax-i5r 1515 ax-ext 2121 |
This theorem depends on definitions: df-bi 116 df-nf 1437 df-sb 1736 df-clab 2126 df-cleq 2132 df-clel 2135 df-if 3475 |
This theorem is referenced by: iftruei 3480 iftrued 3481 ifsbdc 3486 ifcldadc 3501 ifbothdadc 3503 ifbothdc 3504 ifiddc 3505 ifcldcd 3507 ifandc 3508 fidifsnen 6764 nnnninf 7023 mkvprop 7032 uzin 9358 fzprval 9862 fztpval 9863 modifeq2int 10159 bcval 10495 bcval2 10496 sumrbdclem 11146 fsum3cvg 11147 summodclem2a 11150 isumss2 11162 fsum3ser 11166 fsumsplit 11176 sumsplitdc 11201 prodrbdclem 11340 fproddccvg 11341 flodddiv4 11631 gcd0val 11649 dfgcd2 11702 eucalgf 11736 eucalginv 11737 eucalglt 11738 unct 11954 dvexp2 12845 nnsf 13199 nninfsellemsuc 13208 |
Copyright terms: Public domain | W3C validator |