Nuprl Lemma : decomp-map-if-has-value
∀[t,f:Base].  if ispair(t) then t ~ <fst(t), snd(t)> else t ~ Ax fi  supposing (map(f;t))↓
Proof
Definitions occuring in Statement : 
map: map(f;as), 
has-value: (a)↓, 
ifthenelse: if b then t else f fi , 
bfalse: ff, 
btrue: tt, 
uimplies: b supposing a, 
uall: ∀[x:A]. B[x], 
pi1: fst(t), 
pi2: snd(t), 
ispair: if z is a pair then a otherwise b, 
pair: <a, b>, 
base: Base, 
sqequal: s ~ t, 
axiom: Ax
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x], 
member: t ∈ T, 
uimplies: b supposing a, 
map: map(f;as), 
list_ind: list_ind, 
has-value: (a)↓, 
prop: ℙ, 
ifthenelse: if b then t else f fi , 
all: ∀x:A. B[x], 
implies: P ⇒ Q, 
bool: 𝔹, 
or: P ∨ Q, 
pi1: fst(t), 
pi2: snd(t), 
btrue: tt, 
bfalse: ff, 
not: ¬A, 
false: False
Lemmas referenced : 
has-value-if-has-value-map, 
ispair-bool-if-has-value, 
has-value_wf_base, 
base_wf, 
equal_wf, 
bool_wf, 
has-value-implies-dec-ispair, 
has-value-implies-dec-isaxiom, 
bottom_diverge
Rules used in proof : 
cut, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isectElimination, 
thin, 
hypothesisEquality, 
independent_isectElimination, 
hypothesis, 
sqequalRule, 
callbyvalueCallbyvalue, 
callbyvalueReduce, 
because_Cache, 
sqequalIntensionalEquality, 
baseApply, 
closedConclusion, 
baseClosed, 
instantiate, 
isect_memberFormation, 
lambdaFormation, 
unionElimination, 
sqequalAxiom, 
equalityTransitivity, 
equalitySymmetry, 
dependent_functionElimination, 
independent_functionElimination, 
isect_memberEquality, 
voidElimination
Latex:
\mforall{}[t,f:Base].    if  ispair(t)  then  t  \msim{}  <fst(t),  snd(t)>  else  t  \msim{}  Ax  fi    supposing  (map(f;t))\mdownarrow{}
 Date html generated: 
2018_05_21-PM-10_19_16
 Last ObjectModification: 
2017_07_26-PM-06_36_54
Theory : eval!all
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