Nuprl Lemma : cubical-isect_wf
∀[X:⊢]. ∀[A:{X ⊢ _}]. ∀[B:{X.A ⊢ _}].  X ⊢ ⋂A B
Proof
Definitions occuring in Statement : 
cubical-isect: ⋂A B
, 
cube-context-adjoin: X.A
, 
cubical-type: {X ⊢ _}
, 
cubical_set: CubicalSet
, 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
cubical-isect: ⋂A B
, 
cubical-type: {X ⊢ _}
, 
cubical-isect-family: cubical-isect-family(X;A;B;I;a)
, 
subtype_rel: A ⊆r B
, 
uimplies: b supposing a
, 
squash: ↓T
, 
all: ∀x:A. B[x]
, 
true: True
, 
prop: ℙ
, 
guard: {T}
, 
iff: P 
⇐⇒ Q
, 
and: P ∧ Q
, 
rev_implies: P 
⇐ Q
, 
implies: P 
⇒ Q
, 
top: Top
, 
cand: A c∧ B
Lemmas referenced : 
cubical-type_wf, 
cube-context-adjoin_wf, 
cubical_set_wf, 
cubical-isect-family_wf, 
I_cube_wf, 
fset_wf, 
nat_wf, 
names-hom_wf, 
cube-set-restriction_wf, 
nh-comp_wf, 
subtype_rel-equal, 
cubical-type-at_wf, 
cube-set-restriction-comp, 
cc-adjoin-cube_wf, 
equal_wf, 
squash_wf, 
true_wf, 
istype-universe, 
istype-cubical-type-at, 
subtype_rel_self, 
iff_weakening_equal, 
cubical-type-ap-morph_wf, 
nh-comp-assoc, 
cc-adjoin-cube-restriction, 
istype-void, 
nh-id-right, 
cube-set-restriction-id, 
nh-id_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation_alt, 
introduction, 
cut, 
dependent_set_memberEquality_alt, 
sqequalHypSubstitution, 
hypothesis, 
sqequalRule, 
axiomEquality, 
equalityTransitivity, 
equalitySymmetry, 
universeIsType, 
extract_by_obid, 
isectElimination, 
thin, 
hypothesisEquality, 
isect_memberEquality_alt, 
isectIsTypeImplies, 
inhabitedIsType, 
dependent_pairEquality_alt, 
lambdaEquality_alt, 
setElimination, 
rename, 
functionIsType, 
because_Cache, 
applyEquality, 
independent_isectElimination, 
imageElimination, 
dependent_functionElimination, 
natural_numberEquality, 
imageMemberEquality, 
baseClosed, 
instantiate, 
universeEquality, 
productElimination, 
independent_functionElimination, 
lambdaFormation_alt, 
hyp_replacement, 
independent_pairFormation, 
productIsType, 
equalityIstype, 
applyLambdaEquality, 
voidElimination, 
functionExtensionality, 
isectEquality, 
equalityIsType1
Latex:
\mforall{}[X:\mvdash{}].  \mforall{}[A:\{X  \mvdash{}  \_\}].  \mforall{}[B:\{X.A  \mvdash{}  \_\}].    X  \mvdash{}  \mcap{}A  B
Date html generated:
2019_11_05-PM-00_23_27
Last ObjectModification:
2018_12_16-PM-04_53_27
Theory : cubical!type!theory
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