Nuprl Lemma : cubical-subset-term
∀[X:j⊢]. ∀[T:{X ⊢ _}]. ∀[psi:I:fset(ℕ) ⟶ alpha:X(I) ⟶ T(alpha) ⟶ ℙ].
  ∀[t:{X ⊢ _:T}]
    t ∈ {X ⊢ _:{t:T | ∀I,alpha. psi[I;alpha;t]}} supposing ∀I:fset(ℕ). ∀alpha:X(I).  psi[I;alpha;t(alpha)] 
  supposing cubical-type-restriction(X;T;I,a,t.psi[I;a;t])
Proof
Definitions occuring in Statement : 
cubical-subset: cubical-subset, 
cubical-type-restriction: cubical-type-restriction, 
cubical-term-at: u(a)
, 
cubical-term: {X ⊢ _:A}
, 
cubical-type-at: A(a)
, 
cubical-type: {X ⊢ _}
, 
I_cube: A(I)
, 
cubical_set: CubicalSet
, 
fset: fset(T)
, 
nat: ℕ
, 
uimplies: b supposing a
, 
uall: ∀[x:A]. B[x]
, 
prop: ℙ
, 
so_apply: x[s1;s2;s3]
, 
all: ∀x:A. B[x]
, 
member: t ∈ T
, 
function: x:A ⟶ B[x]
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
uimplies: b supposing a
, 
member: t ∈ T
, 
cubical-term: {X ⊢ _:A}
, 
all: ∀x:A. B[x]
, 
subtype_rel: A ⊆r B
, 
so_lambda: so_lambda3, 
prop: ℙ
, 
so_apply: x[s1;s2;s3]
, 
cubical-term-at: u(a)
, 
cubical-subset: cubical-subset, 
guard: {T}
, 
squash: ↓T
, 
true: True
, 
iff: P 
⇐⇒ Q
, 
and: P ∧ Q
, 
rev_implies: P 
⇐ Q
, 
implies: P 
⇒ Q
Lemmas referenced : 
names-hom_wf, 
I_cube_wf, 
istype-cubical-type-at, 
cube-set-restriction_wf, 
cubical-subset_wf, 
cubical-type-ap-morph_wf, 
cubical-term-at_wf, 
cubical-term_wf, 
cubical-type-cumulativity2, 
cubical_set_cumulativity-i-j, 
cubical-type-restriction_wf, 
fset_wf, 
nat_wf, 
cubical-type_wf, 
cubical_set_wf, 
cubical_type_at_pair_lemma, 
cubical_type_ap_morph_pair_lemma, 
equal_wf, 
squash_wf, 
true_wf, 
istype-universe, 
cubical-type-at_wf, 
subtype_rel_self, 
iff_weakening_equal
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation_alt, 
cut, 
sqequalHypSubstitution, 
setElimination, 
thin, 
rename, 
dependent_set_memberEquality_alt, 
sqequalRule, 
functionIsType, 
because_Cache, 
universeIsType, 
introduction, 
extract_by_obid, 
isectElimination, 
hypothesisEquality, 
hypothesis, 
equalityIstype, 
instantiate, 
applyEquality, 
lambdaEquality_alt, 
cumulativity, 
inhabitedIsType, 
independent_isectElimination, 
universeEquality, 
functionExtensionality, 
dependent_functionElimination, 
Error :memTop, 
lambdaFormation_alt, 
equalitySymmetry, 
imageElimination, 
equalityTransitivity, 
natural_numberEquality, 
imageMemberEquality, 
baseClosed, 
productElimination, 
independent_functionElimination
Latex:
\mforall{}[X:j\mvdash{}].  \mforall{}[T:\{X  \mvdash{}  \_\}].  \mforall{}[psi:I:fset(\mBbbN{})  {}\mrightarrow{}  alpha:X(I)  {}\mrightarrow{}  T(alpha)  {}\mrightarrow{}  \mBbbP{}].
    \mforall{}[t:\{X  \mvdash{}  \_:T\}]
        t  \mmember{}  \{X  \mvdash{}  \_:\{t:T  |  \mforall{}I,alpha.  psi[I;alpha;t]\}\} 
        supposing  \mforall{}I:fset(\mBbbN{}).  \mforall{}alpha:X(I).    psi[I;alpha;t(alpha)] 
    supposing  cubical-type-restriction(X;T;I,a,t.psi[I;a;t])
Date html generated:
2020_05_20-PM-03_13_49
Last ObjectModification:
2020_04_06-PM-05_17_59
Theory : cubical!type!theory
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