Nuprl Lemma : cubical-type-cumulativity-i-j
∀[X:j⊢]. ({X ⊢j _} ⊆r cubical-type{[j | i]:l}(X))
Proof
Definitions occuring in Statement : 
cubical-type: {X ⊢ _}
, 
cubical_set: CubicalSet
, 
subtype_rel: A ⊆r B
, 
uall: ∀[x:A]. B[x]
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
subtype_rel: A ⊆r B
, 
member: t ∈ T
, 
cubical-type: {X ⊢ _}
, 
and: P ∧ Q
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
uimplies: b supposing a
, 
all: ∀x:A. B[x]
, 
squash: ↓T
, 
prop: ℙ
, 
true: True
, 
guard: {T}
, 
iff: P 
⇐⇒ Q
, 
rev_implies: P 
⇐ Q
, 
implies: P 
⇒ Q
Lemmas referenced : 
subtype_rel_dep_function, 
I_cube_wf, 
fset_wf, 
nat_wf, 
names-hom_wf, 
cube-set-restriction_wf, 
nh-id_wf, 
subtype_rel-equal, 
equal_wf, 
squash_wf, 
true_wf, 
istype-universe, 
cube-set-restriction-id, 
subtype_rel_self, 
iff_weakening_equal, 
nh-comp_wf, 
cube-set-restriction-comp, 
cubical-type_wf, 
cubical_set_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation_alt, 
lambdaEquality_alt, 
sqequalHypSubstitution, 
setElimination, 
thin, 
rename, 
cut, 
productElimination, 
dependent_set_memberEquality_alt, 
dependent_pairEquality_alt, 
functionExtensionality, 
applyEquality, 
hypothesisEquality, 
hypothesis, 
instantiate, 
introduction, 
extract_by_obid, 
isectElimination, 
cumulativity, 
sqequalRule, 
universeEquality, 
universeIsType, 
because_Cache, 
independent_isectElimination, 
lambdaFormation_alt, 
functionIsType, 
inhabitedIsType, 
productIsType, 
equalityIstype, 
imageElimination, 
equalityTransitivity, 
equalitySymmetry, 
natural_numberEquality, 
imageMemberEquality, 
baseClosed, 
independent_functionElimination, 
dependent_functionElimination
Latex:
\mforall{}[X:j\mvdash{}].  (\{X  \mvdash{}j  \_\}  \msubseteq{}r  cubical-type\{[j  |  i]:l\}(X))
Date html generated:
2020_05_20-PM-01_47_23
Last ObjectModification:
2020_04_03-PM-07_58_46
Theory : cubical!type!theory
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