Nuprl Lemma : decidable__equal_function
∀[T:Type]. ((∀x,y:T.  Dec(x = y ∈ T)) 
⇒ (∀i,j:ℤ. ∀f,g:{i..j-} ⟶ T.  Dec(f = g ∈ ({i..j-} ⟶ T))))
Proof
Definitions occuring in Statement : 
int_seg: {i..j-}
, 
decidable: Dec(P)
, 
uall: ∀[x:A]. B[x]
, 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
function: x:A ⟶ B[x]
, 
int: ℤ
, 
universe: Type
, 
equal: s = t ∈ T
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
implies: P 
⇒ Q
, 
all: ∀x:A. B[x]
, 
member: t ∈ T
, 
prop: ℙ
, 
so_lambda: λ2x.t[x]
, 
nat: ℕ
, 
so_apply: x[s]
, 
false: False
, 
not: ¬A
, 
or: P ∨ Q
, 
decidable: Dec(P)
, 
true: True
, 
less_than': less_than'(a;b)
, 
squash: ↓T
, 
less_than: a < b
, 
nat_plus: ℕ+
, 
uimplies: b supposing a
, 
uiff: uiff(P;Q)
, 
subtype_rel: A ⊆r B
, 
top: Top
, 
subtract: n - m
, 
le: A ≤ B
, 
and: P ∧ Q
, 
lelt: i ≤ j < k
, 
int_seg: {i..j-}
, 
iff: P 
⇐⇒ Q
, 
rev_implies: P 
⇐ Q
, 
sq_type: SQType(T)
, 
guard: {T}
, 
sq_stable: SqStable(P)
Lemmas referenced : 
decidable_wf, 
equal_wf, 
istype-universe, 
istype-le, 
subtract_wf, 
int_seg_wf, 
istype-int, 
istype-less_than, 
primrec-wf2, 
le_wf, 
istype-nat, 
istype-void, 
le-add-cancel, 
mul-distributes, 
mul-associates, 
omega-shadow, 
add-zero, 
minus-zero, 
zero-add, 
zero-mul, 
mul-distributes-right, 
two-mul, 
add-mul-special, 
add-swap, 
one-mul, 
add-associates, 
minus-one-mul-top, 
le_reflexive, 
add_functionality_wrt_le, 
less-iff-le, 
int_subtype_base, 
add-is-int-iff, 
add-commutes, 
minus-one-mul, 
int_seg_properties, 
decidable__le, 
istype-false, 
not-le-2, 
condition-implies-le, 
minus-add, 
minus-minus, 
le-add-cancel-alt, 
subtype_rel_function, 
int_seg_subtype, 
le-add-cancel2, 
subtype_rel_self, 
decidable__lt, 
not-lt-2, 
mul-swap, 
mul-commutes, 
decidable__equal_int, 
subtype_base_sq, 
not-equal-2, 
iff_weakening_equal, 
true_wf, 
squash_wf, 
equal_functionality_wrt_subtype_rel2, 
sq_stable__le, 
subtract_nat_wf, 
le_weakening2
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
Error :isect_memberFormation_alt, 
Error :lambdaFormation_alt, 
cut, 
sqequalRule, 
Error :functionIsType, 
Error :universeIsType, 
hypothesisEquality, 
because_Cache, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
hypothesis, 
instantiate, 
universeEquality, 
rename, 
setElimination, 
Error :inhabitedIsType, 
natural_numberEquality, 
functionEquality, 
Error :setIsType, 
Error :lambdaEquality_alt, 
intEquality, 
Error :equalityIstype, 
Error :functionExtensionality_alt, 
Error :inlFormation_alt, 
independent_functionElimination, 
imageMemberEquality, 
independent_pairFormation, 
Error :dependent_set_memberEquality_alt, 
equalitySymmetry, 
equalityTransitivity, 
multiplyEquality, 
addEquality, 
dependent_functionElimination, 
independent_isectElimination, 
applyEquality, 
baseClosed, 
closedConclusion, 
baseApply, 
voidElimination, 
Error :isect_memberEquality_alt, 
productElimination, 
unionElimination, 
minusEquality, 
Error :productIsType, 
cumulativity, 
applyLambdaEquality, 
imageElimination, 
Error :inrFormation_alt
Latex:
\mforall{}[T:Type].  ((\mforall{}x,y:T.    Dec(x  =  y))  {}\mRightarrow{}  (\mforall{}i,j:\mBbbZ{}.  \mforall{}f,g:\{i..j\msupminus{}\}  {}\mrightarrow{}  T.    Dec(f  =  g)))
Date html generated:
2019_06_20-PM-00_42_04
Last ObjectModification:
2019_01_02-PM-00_24_16
Theory : list_0
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