Nuprl Lemma : discrete-function_wf
∀[A:Type]. ∀[B:A ⟶ Type]. ∀[X:j⊢]. ∀[f:{X ⊢ _:Πdiscr(A) discrete-family(A;a.B[a])}].
  (discrete-function(f) ∈ {X ⊢ _:discr(a:A ⟶ B[a])})
Proof
Definitions occuring in Statement : 
discrete-function: discrete-function(f)
, 
discrete-family: discrete-family(A;a.B[a])
, 
discrete-cubical-type: discr(T)
, 
cubical-pi: ΠA B
, 
cubical-term: {X ⊢ _:A}
, 
cubical_set: CubicalSet
, 
uall: ∀[x:A]. B[x]
, 
so_apply: x[s]
, 
member: t ∈ T
, 
function: x:A ⟶ B[x]
, 
universe: Type
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
discrete-function: discrete-function(f)
, 
cubical-term: {X ⊢ _:A}
, 
discrete-cubical-type: discr(T)
, 
all: ∀x:A. B[x]
, 
so_apply: x[s]
, 
so_lambda: λ2x.t[x]
, 
cubical-pi: ΠA B
, 
cubical-pi-family: cubical-pi-family(X;A;B;I;a)
, 
subtype_rel: A ⊆r B
, 
cc-adjoin-cube: (v;u)
, 
discrete-family: discrete-family(A;a.B[a])
, 
pi2: snd(t)
, 
squash: ↓T
, 
prop: ℙ
, 
true: True
, 
implies: P 
⇒ Q
, 
uimplies: b supposing a
, 
cubical-type-at: A(a)
, 
pi1: fst(t)
, 
cube-context-adjoin: X.A
, 
guard: {T}
, 
iff: P 
⇐⇒ Q
, 
and: P ∧ Q
, 
rev_implies: P 
⇐ Q
Lemmas referenced : 
cubical_type_at_pair_lemma, 
cubical_type_ap_morph_pair_lemma, 
fset_wf, 
nat_wf, 
names-hom_wf, 
I_cube_wf, 
istype-cubical-type-at, 
cube-set-restriction_wf, 
discrete-cubical-type_wf, 
cubical-type-ap-morph_wf, 
cubical-term_wf, 
cubical-pi_wf, 
discrete-family_wf, 
cubical_set_wf, 
istype-universe, 
nh-id_wf, 
equal_wf, 
squash_wf, 
true_wf, 
subtype_rel-equal, 
cubical-type-at_wf, 
cube_set_restriction_pair_lemma, 
nh-id-left, 
nh-comp_wf, 
subtype_rel_self, 
iff_weakening_equal, 
nh-id-right
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation_alt, 
introduction, 
cut, 
dependent_set_memberEquality_alt, 
sqequalRule, 
extract_by_obid, 
sqequalHypSubstitution, 
dependent_functionElimination, 
thin, 
Error :memTop, 
hypothesis, 
functionIsType, 
universeIsType, 
isectElimination, 
because_Cache, 
hypothesisEquality, 
equalityIstype, 
functionEquality, 
applyEquality, 
axiomEquality, 
equalityTransitivity, 
equalitySymmetry, 
instantiate, 
cumulativity, 
lambdaEquality_alt, 
isect_memberEquality_alt, 
isectIsTypeImplies, 
inhabitedIsType, 
universeEquality, 
setElimination, 
rename, 
functionExtensionality, 
hyp_replacement, 
lambdaFormation_alt, 
applyLambdaEquality, 
imageMemberEquality, 
baseClosed, 
imageElimination, 
natural_numberEquality, 
independent_functionElimination, 
independent_isectElimination, 
productElimination
Latex:
\mforall{}[A:Type].  \mforall{}[B:A  {}\mrightarrow{}  Type].  \mforall{}[X:j\mvdash{}].  \mforall{}[f:\{X  \mvdash{}  \_:\mPi{}discr(A)  discrete-family(A;a.B[a])\}].
    (discrete-function(f)  \mmember{}  \{X  \mvdash{}  \_:discr(a:A  {}\mrightarrow{}  B[a])\})
Date html generated:
2020_05_20-PM-03_38_52
Last ObjectModification:
2020_04_07-PM-04_29_33
Theory : cubical!type!theory
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