Nuprl Lemma : discrete-fun-app-invariant
∀[A,B:Type]. ∀[f:{() ⊢ _:(discr(A) ⟶ discr(B))}]. ∀[I:fset(ℕ)]. ∀[a:()(I)]. ∀[t:A].
  (app(f; discr(t))(a) = app(f; discr(t))(⋅) ∈ B)
Proof
Definitions occuring in Statement : 
discrete-cubical-term: discr(t)
, 
discrete-cubical-type: discr(T)
, 
cubical-app: app(w; u)
, 
cubical-fun: (A ⟶ B)
, 
cubical-term-at: u(a)
, 
cubical-term: {X ⊢ _:A}
, 
trivial-cube-set: ()
, 
I_cube: A(I)
, 
empty-fset: {}
, 
fset: fset(T)
, 
nat: ℕ
, 
it: ⋅
, 
uall: ∀[x:A]. B[x]
, 
universe: Type
, 
equal: s = t ∈ T
Definitions unfolded in proof : 
cubical-term-at: u(a)
, 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
discrete-cubical-term: discr(t)
, 
cubical-app: app(w; u)
, 
discrete-cubical-type: discr(T)
, 
cubical-fun: (A ⟶ B)
, 
all: ∀x:A. B[x]
, 
top: Top
, 
cubical-fun-family: cubical-fun-family(X; A; B; I; a)
, 
squash: ↓T
, 
cubical-term: {X ⊢ _:A}
, 
subtype_rel: A ⊆r B
, 
unit: Unit
, 
I_cube: A(I)
, 
functor-ob: ob(F)
, 
pi1: fst(t)
, 
trivial-cube-set: ()
, 
prop: ℙ
, 
implies: P 
⇒ Q
, 
names-hom: I ⟶ J
, 
names: names(I)
, 
false: False
, 
true: True
, 
cubical-type-at: A(a)
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
uimplies: b supposing a
, 
guard: {T}
Lemmas referenced : 
discrete-fun-invariant, 
I_cube_wf, 
trivial-cube-set_wf, 
fset_wf, 
nat_wf, 
cubical-term_wf, 
cubical-fun_wf, 
discrete-cubical-type_wf, 
cubical_type_at_pair_lemma, 
cubical_type_ap_morph_pair_lemma, 
empty-fset_wf, 
it_wf, 
subtype_rel_self, 
equal-wf-base, 
cubical-type-at_wf, 
equal_wf, 
dM0_wf, 
names_wf, 
member-empty-fset, 
squash_wf, 
true_wf, 
nh-id_wf, 
subtype_rel_dep_function, 
names-hom_wf, 
cube-set-restriction_wf, 
equal_functionality_wrt_subtype_rel2
Rules used in proof : 
sqequalSubstitution, 
sqequalRule, 
sqequalReflexivity, 
sqequalTransitivity, 
computationStep, 
cut, 
introduction, 
extract_by_obid, 
isect_memberFormation, 
hypothesis, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
hypothesisEquality, 
cumulativity, 
universeEquality, 
dependent_functionElimination, 
isect_memberEquality, 
voidElimination, 
voidEquality, 
applyLambdaEquality, 
setElimination, 
rename, 
imageMemberEquality, 
baseClosed, 
imageElimination, 
applyEquality, 
functionExtensionality, 
intEquality, 
because_Cache, 
lambdaFormation, 
equalityTransitivity, 
equalitySymmetry, 
independent_functionElimination, 
lambdaEquality, 
hyp_replacement, 
natural_numberEquality, 
functionEquality, 
independent_isectElimination
Latex:
\mforall{}[A,B:Type].  \mforall{}[f:\{()  \mvdash{}  \_:(discr(A)  {}\mrightarrow{}  discr(B))\}].  \mforall{}[I:fset(\mBbbN{})].  \mforall{}[a:()(I)].  \mforall{}[t:A].
    (app(f;  discr(t))(a)  =  app(f;  discr(t))(\mcdot{}))
Date html generated:
2017_10_05-AM-02_12_20
Last ObjectModification:
2017_03_02-PM-11_21_26
Theory : cubical!type!theory
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