Nuprl Lemma : path-type-subtype
∀[X:j⊢]. ∀[A:{X ⊢ _}]. ∀[a,b:{X ⊢ _:A}].  ({X ⊢ _:(Path_A a b)} ⊆r {X ⊢ _:Path(A)})
Proof
Definitions occuring in Statement : 
path-type: (Path_A a b)
, 
pathtype: Path(A)
, 
cubical-term: {X ⊢ _:A}
, 
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]
, 
member: t ∈ T
, 
subtype_rel: A ⊆r B
, 
cubical-term: {X ⊢ _:A}
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
uimplies: b supposing a
, 
all: ∀x:A. B[x]
, 
cubical-type-ap-morph: (u a f)
, 
pi2: snd(t)
, 
pathtype: Path(A)
, 
cubical-fun: (A ⟶ B)
, 
path-type: (Path_A a b)
, 
cubical-subset: cubical-subset
Lemmas referenced : 
subtype_rel_dep_function, 
I_cube_wf, 
cubical-type-at_wf, 
path-type_wf, 
cubical_set_cumulativity-i-j, 
cubical-type-cumulativity2, 
pathtype_wf, 
path-type-at-subtype, 
fset_wf, 
nat_wf, 
cube-set-restriction_wf, 
names-hom_wf, 
istype-cubical-type-at, 
cubical-type-ap-morph_wf, 
cubical-term_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation_alt, 
introduction, 
cut, 
lambdaEquality_alt, 
sqequalHypSubstitution, 
setElimination, 
thin, 
rename, 
dependent_set_memberEquality_alt, 
functionExtensionality, 
applyEquality, 
hypothesisEquality, 
hypothesis, 
instantiate, 
extract_by_obid, 
isectElimination, 
cumulativity, 
sqequalRule, 
universeIsType, 
because_Cache, 
independent_isectElimination, 
lambdaFormation_alt, 
dependent_functionElimination, 
inhabitedIsType, 
functionIsType, 
equalityIstype, 
axiomEquality, 
isect_memberEquality_alt, 
isectIsTypeImplies
Latex:
\mforall{}[X:j\mvdash{}].  \mforall{}[A:\{X  \mvdash{}  \_\}].  \mforall{}[a,b:\{X  \mvdash{}  \_:A\}].    (\{X  \mvdash{}  \_:(Path\_A  a  b)\}  \msubseteq{}r  \{X  \mvdash{}  \_:Path(A)\})
Date html generated:
2020_05_20-PM-03_14_58
Last ObjectModification:
2020_04_06-PM-05_36_40
Theory : cubical!type!theory
Home
Index