Nuprl Lemma : discrete-fun-at
∀[A,B:Type]. ∀[f:{() ⊢ _:(discr(A) ⟶ discr(B))}]. ∀[I:fset(ℕ)]. ∀[a:()(I)].
  ((f I a) = (λJ,h,u. (f {} ⋅ {} 1 u)) ∈ (discr(A) ⟶ discr(B))(a))
Proof
Definitions occuring in Statement : 
discrete-cubical-type: discr(T), 
cubical-fun: (A ⟶ B), 
cubical-term: {X ⊢ _:A}, 
cubical-type-at: A(a), 
trivial-cube-set: (), 
I_cube: A(I), 
nh-id: 1, 
empty-fset: {}, 
fset: fset(T), 
nat: ℕ, 
it: ⋅, 
uall: ∀[x:A]. B[x], 
apply: f a, 
lambda: λx.A[x], 
universe: Type, 
equal: s = t ∈ T
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x], 
member: t ∈ T, 
discrete-cubical-type: discr(T), 
cubical-fun: (A ⟶ B), 
cubical-fun-family: cubical-fun-family(X; A; B; I; a), 
all: ∀x:A. B[x], 
top: Top, 
cubical-term: {X ⊢ _:A}, 
cubical-type-at: A(a), 
pi1: fst(t), 
so_lambda: λ2x.t[x], 
so_apply: x[s], 
prop: ℙ, 
trivial-cube-set: (), 
cubical-type-ap-morph: (u a f), 
pi2: snd(t), 
subtype_rel: A ⊆r B, 
I_cube: A(I), 
functor-ob: ob(F), 
unit: Unit, 
squash: ↓T, 
true: True, 
uimplies: b supposing a, 
guard: {T}, 
iff: P ⇐⇒ Q, 
and: P ∧ Q, 
rev_implies: P ⇐ Q, 
implies: P ⇒ Q, 
names-hom: I ⟶ J, 
names: names(I), 
false: False, 
nh-id: 1, 
nh-comp: g ⋅ f, 
dma-lift-compose: dma-lift-compose(I;J;eqi;eqj;f;g), 
compose: f o g, 
dM: dM(I), 
dM-lift: dM-lift(I;J;f)
Lemmas referenced : 
I_cube_wf, 
fset_wf, 
nat_wf, 
cubical-term_wf, 
trivial-cube-set_wf, 
cubical-fun_wf, 
discrete-cubical-type_wf, 
cubical_type_at_pair_lemma, 
cubical_type_ap_morph_pair_lemma, 
names-hom_wf, 
all_wf, 
equal_wf, 
nh-comp_wf, 
I_cube_pair_redex_lemma, 
cube_set_restriction_pair_lemma, 
subtype_rel_self, 
equal-wf-base, 
nh-id_wf, 
squash_wf, 
true_wf, 
nh-id-left, 
iff_weakening_equal, 
empty-fset_wf, 
dM0_wf, 
names_wf, 
it_wf, 
member-empty-fset, 
dM-lift-0-sq, 
set_wf, 
nh-id-right
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
cut, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
because_Cache, 
hypothesisEquality, 
hypothesis, 
cumulativity, 
universeEquality, 
promote_hyp, 
sqequalRule, 
dependent_functionElimination, 
isect_memberEquality, 
voidElimination, 
voidEquality, 
setElimination, 
rename, 
dependent_set_memberEquality, 
lambdaFormation, 
lambdaEquality, 
applyEquality, 
functionExtensionality, 
intEquality, 
baseClosed, 
applyLambdaEquality, 
hyp_replacement, 
equalitySymmetry, 
imageElimination, 
equalityTransitivity, 
natural_numberEquality, 
imageMemberEquality, 
setEquality, 
independent_isectElimination, 
productElimination, 
independent_functionElimination, 
functionEquality
Latex:
\mforall{}[A,B:Type].  \mforall{}[f:\{()  \mvdash{}  \_:(discr(A)  {}\mrightarrow{}  discr(B))\}].  \mforall{}[I:fset(\mBbbN{})].  \mforall{}[a:()(I)].
    ((f  I  a)  =  (\mlambda{}J,h,u.  (f  \{\}  \mcdot{}  \{\}  1  u)))
Date html generated:
2017_10_05-AM-02_12_05
Last ObjectModification:
2017_03_02-PM-11_21_53
Theory : cubical!type!theory
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