Theorem iffalsed 3361

Description: Value of the conditional operator when its first argument is false. (Contributed by Glauco Siliprandi, 11-Dec-2019.)

Hypothesis

Ref	Expression
iffalsed.1	⊢ (𝜑 → ¬ 𝜒)

Assertion

Ref	Expression
iffalsed	⊢ (𝜑 → if(𝜒, 𝐴, 𝐵) = 𝐵)

Proof of Theorem iffalsed

Step	Hyp	Ref	Expression
1		iffalsed.1	. 2 ⊢ (𝜑 → ¬ 𝜒)
2		iffalse 3359	. 2 ⊢ (¬ 𝜒 → if(𝜒, 𝐴, 𝐵) = 𝐵)
3	1, 2	syl 14	1 ⊢ (𝜑 → if(𝜒, 𝐴, 𝐵) = 𝐵)

Syntax hints:  ¬ wn 3   → wi 4   = wceq 1284  ifcif 3351

This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 104  ax-ia2 105  ax-ia3 106  ax-in2 577  ax-io 662  ax-5 1376  ax-7 1377  ax-gen 1378  ax-ie1 1422  ax-ie2 1423  ax-8 1435  ax-11 1437  ax-4 1440  ax-17 1459  ax-i9 1463  ax-ial 1467  ax-i5r 1468  ax-ext 2063

This theorem depends on definitions:  df-bi 115  df-nf 1390  df-sb 1686  df-clab 2068  df-cleq 2074  df-clel 2077  df-if 3352

This theorem is referenced by:  fzprval  9099  expinnval  9479  expnegap0  9484  gcdval  10351  eucalgf  10437  eucalginv  10438  eucalglt  10439