Nuprl Lemma : ifthenelse_wf-partial
∀T:Type. (value-type(T) 
⇒ (∀c1,c2:partial(T). ∀b:partial(𝔹).  (if b then c1 else c2 fi  ∈ partial(T))))
Proof
Definitions occuring in Statement : 
partial: partial(T)
, 
value-type: value-type(T)
, 
ifthenelse: if b then t else f fi 
, 
bool: 𝔹
, 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
member: t ∈ T
, 
universe: Type
Definitions unfolded in proof : 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
member: t ∈ T
, 
partial: partial(T)
, 
quotient: x,y:A//B[x; y]
, 
and: P ∧ Q
, 
uall: ∀[x:A]. B[x]
, 
prop: ℙ
, 
base-partial: base-partial(T)
, 
uimplies: b supposing a
, 
bool: 𝔹
, 
subtype_rel: A ⊆r B
, 
so_lambda: λ2x y.t[x; y]
, 
so_apply: x[s1;s2]
, 
per-partial: per-partial(T;x;y)
, 
uiff: uiff(P;Q)
, 
sq_type: SQType(T)
, 
guard: {T}
, 
not: ¬A
, 
false: False
, 
squash: ↓T
, 
true: True
, 
iff: P 
⇐⇒ Q
, 
rev_implies: P 
⇐ Q
Lemmas referenced : 
base-partial_wf, 
bool_wf, 
per-partial_wf, 
equal_wf, 
equal-wf-base, 
partial_wf, 
value-type_wf, 
has-value_wf-partial, 
union-value-type, 
unit_wf2, 
subtype_quotient, 
per-partial-equiv_rel, 
is-exception_wf, 
subtype_base_sq, 
bool_subtype_base, 
base-partial-not-exception, 
sqle_wf_base, 
squash_wf, 
true_wf, 
base_wf, 
iff_weakening_equal, 
ifthenelse_wf-partial-base
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation, 
cut, 
sqequalHypSubstitution, 
pointwiseFunctionalityForEquality, 
because_Cache, 
sqequalRule, 
pertypeElimination, 
productElimination, 
thin, 
equalityTransitivity, 
hypothesis, 
equalitySymmetry, 
introduction, 
extract_by_obid, 
isectElimination, 
rename, 
setElimination, 
hypothesisEquality, 
dependent_functionElimination, 
independent_functionElimination, 
productEquality, 
cumulativity, 
universeEquality, 
sqequalSqle, 
divergentSqle, 
independent_isectElimination, 
applyEquality, 
lambdaEquality, 
instantiate, 
sqleReflexivity, 
voidElimination, 
imageElimination, 
natural_numberEquality, 
imageMemberEquality, 
baseClosed
Latex:
\mforall{}T:Type
    (value-type(T)  {}\mRightarrow{}  (\mforall{}c1,c2:partial(T).  \mforall{}b:partial(\mBbbB{}).    (if  b  then  c1  else  c2  fi    \mmember{}  partial(T))))
Date html generated:
2017_04_14-AM-07_41_08
Last ObjectModification:
2017_02_27-PM-03_13_10
Theory : partial_1
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