Nuprl Lemma : inl-do-apply
∀[A,B:Type]. ∀[f:A ⟶ (B + Top)]. ∀[x:A].  inl do-apply(f;x) ~ f x supposing ↑can-apply(f;x)
Proof
Definitions occuring in Statement : 
do-apply: do-apply(f;x), 
can-apply: can-apply(f;x), 
assert: ↑b, 
uimplies: b supposing a, 
uall: ∀[x:A]. B[x], 
top: Top, 
apply: f a, 
function: x:A ⟶ B[x], 
inl: inl x, 
union: left + right, 
universe: Type, 
sqequal: s ~ t
Definitions unfolded in proof : 
do-apply: do-apply(f;x), 
can-apply: can-apply(f;x), 
member: t ∈ T, 
all: ∀x:A. B[x], 
implies: P ⇒ Q, 
isl: isl(x), 
outl: outl(x), 
assert: ↑b, 
ifthenelse: if b then t else f fi , 
btrue: tt, 
prop: ℙ, 
bfalse: ff, 
false: False, 
uall: ∀[x:A]. B[x], 
subtype_rel: A ⊆r B, 
uimplies: b supposing a, 
top: Top
Lemmas referenced : 
top_wf, 
true_wf, 
false_wf, 
equal_wf, 
assert_wf, 
can-apply_wf, 
subtype_rel_union
Rules used in proof : 
cut, 
thin, 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
applyEquality, 
functionExtensionality, 
hypothesisEquality, 
cumulativity, 
unionEquality, 
introduction, 
extract_by_obid, 
hypothesis, 
lambdaFormation, 
unionElimination, 
sqequalRule, 
sqequalHypSubstitution, 
voidElimination, 
isectElimination, 
equalityTransitivity, 
equalitySymmetry, 
dependent_functionElimination, 
independent_functionElimination, 
because_Cache, 
independent_isectElimination, 
lambdaEquality, 
isect_memberEquality, 
voidEquality, 
functionEquality, 
universeEquality, 
isect_memberFormation, 
sqequalAxiom
Latex:
\mforall{}[A,B:Type].  \mforall{}[f:A  {}\mrightarrow{}  (B  +  Top)].  \mforall{}[x:A].    inl  do-apply(f;x)  \msim{}  f  x  supposing  \muparrow{}can-apply(f;x)
Date html generated:
2017_10_01-AM-09_13_17
Last ObjectModification:
2017_07_26-PM-04_48_45
Theory : general
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