Nuprl Lemma : decide_wf
∀[T1,T2,T3:Type]. ∀[x:T1 + T2]. ∀[l:T1 ⟶ T3]. ∀[r:T2 ⟶ T3].  (case x of inl(a) => l[a] | inr(b) => r[b] ∈ T3)
Proof
Definitions occuring in Statement : 
uall: ∀[x:A]. B[x]
, 
so_apply: x[s]
, 
member: t ∈ T
, 
function: x:A ⟶ B[x]
, 
decide: case b of inl(x) => s[x] | inr(y) => t[y]
, 
union: left + right
, 
universe: Type
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
so_apply: x[s]
, 
prop: ℙ
Lemmas referenced : 
equal_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
introduction, 
cut, 
hypothesisEquality, 
equalityTransitivity, 
hypothesis, 
equalitySymmetry, 
thin, 
unionEquality, 
lambdaFormation, 
unionElimination, 
sqequalRule, 
applyEquality, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
dependent_functionElimination, 
independent_functionElimination, 
axiomEquality, 
functionEquality, 
isect_memberEquality, 
because_Cache, 
universeEquality
Latex:
\mforall{}[T1,T2,T3:Type].  \mforall{}[x:T1  +  T2].  \mforall{}[l:T1  {}\mrightarrow{}  T3].  \mforall{}[r:T2  {}\mrightarrow{}  T3].
    (case  x  of  inl(a)  =>  l[a]  |  inr(b)  =>  r[b]  \mmember{}  T3)
Date html generated:
2019_10_15-AM-11_06_47
Last ObjectModification:
2018_08_21-PM-01_58_34
Theory : general
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