Nuprl Lemma : apply-ifthenelse2
∀[T1,U1,T2,U2:Type]. ∀[x:T1]. ∀[y:T2]. ∀[b:𝔹]. ∀[f:if b then T1 ⟶ U1 else T2 ⟶ U2 fi ].
  (f[if b then x else y fi ] ~ if b then f[x] else f[y] fi )
Proof
Definitions occuring in Statement : 
ifthenelse: if b then t else f fi 
, 
bool: 𝔹
, 
uall: ∀[x:A]. B[x]
, 
so_apply: x[s]
, 
function: x:A ⟶ B[x]
, 
universe: Type
, 
sqequal: s ~ t
Definitions unfolded in proof : 
bool: 𝔹
, 
ifthenelse: if b then t else f fi 
, 
member: t ∈ T
, 
uall: ∀[x:A]. B[x]
Lemmas referenced : 
ifthenelse_wf, 
bool_wf
Rules used in proof : 
sqequalHypSubstitution, 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
unionElimination, 
thin, 
sqequalRule, 
cut, 
instantiate, 
lemma_by_obid, 
isectElimination, 
hypothesisEquality, 
universeEquality, 
functionEquality, 
hypothesis, 
because_Cache, 
isect_memberFormation, 
introduction, 
sqequalAxiom, 
isect_memberEquality
Latex:
\mforall{}[T1,U1,T2,U2:Type].  \mforall{}[x:T1].  \mforall{}[y:T2].  \mforall{}[b:\mBbbB{}].  \mforall{}[f:if  b  then  T1  {}\mrightarrow{}  U1  else  T2  {}\mrightarrow{}  U2  fi  ].
    (f[if  b  then  x  else  y  fi  ]  \msim{}  if  b  then  f[x]  else  f[y]  fi  )
Date html generated:
2016_05_13-PM-04_01_26
Last ObjectModification:
2015_12_26-AM-10_49_08
Theory : bool_1
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