Nuprl Lemma : path-type-ext-eq
∀[X:j⊢]. ∀[A:{X ⊢ _}]. ∀[a,b:{X ⊢ _:A}].
  {t:{X ⊢ _:Path(A)}| (t @ 0(𝕀) = a ∈ {X ⊢ _:A}) ∧ (t @ 1(𝕀) = b ∈ {X ⊢ _:A})}  ≡ {X ⊢ _:(Path_A a b)}
Proof
Definitions occuring in Statement : 
path-type: (Path_A a b)
, 
cubicalpath-app: pth @ r
, 
pathtype: Path(A)
, 
interval-1: 1(𝕀)
, 
interval-0: 0(𝕀)
, 
cubical-term: {X ⊢ _:A}
, 
cubical-type: {X ⊢ _}
, 
cubical_set: CubicalSet
, 
ext-eq: A ≡ B
, 
uall: ∀[x:A]. B[x]
, 
and: P ∧ Q
, 
set: {x:A| B[x]} 
, 
equal: s = t ∈ T
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
ext-eq: A ≡ B
, 
and: P ∧ Q
, 
subtype_rel: A ⊆r B
, 
cubical-term: {X ⊢ _:A}
, 
path-type: (Path_A a b)
, 
cubical-subset: cubical-subset, 
all: ∀x:A. B[x]
, 
cand: A c∧ B
, 
pathtype: Path(A)
, 
cubical-fun: (A ⟶ B)
, 
cubical-fun-family: cubical-fun-family(X; A; B; I; a)
, 
uimplies: b supposing a
, 
squash: ↓T
, 
true: True
, 
respects-equality: respects-equality(S;T)
, 
implies: P 
⇒ Q
, 
prop: ℙ
, 
interval-0: 0(𝕀)
, 
cubicalpath-app: pth @ r
, 
cubical-term-at: u(a)
, 
cubical-app: app(w; u)
, 
interval-1: 1(𝕀)
, 
guard: {T}
, 
lattice-point: Point(l)
, 
record-select: r.x
, 
dM: dM(I)
, 
free-DeMorgan-algebra: free-DeMorgan-algebra(T;eq)
, 
mk-DeMorgan-algebra: mk-DeMorgan-algebra(L;n)
, 
record-update: r[x := v]
, 
ifthenelse: if b then t else f fi 
, 
eq_atom: x =a y
, 
bfalse: ff
, 
free-DeMorgan-lattice: free-DeMorgan-lattice(T;eq)
, 
free-dist-lattice: free-dist-lattice(T; eq)
, 
mk-bounded-distributive-lattice: mk-bounded-distributive-lattice, 
mk-bounded-lattice: mk-bounded-lattice(T;m;j;z;o)
, 
btrue: tt
, 
cubical-type-at: A(a)
, 
pi1: fst(t)
, 
interval-type: 𝕀
, 
constant-cubical-type: (X)
, 
I_cube: A(I)
, 
functor-ob: ob(F)
, 
interval-presheaf: 𝕀
, 
cubical-path-app: pth @ r
Lemmas referenced : 
cubical-term_wf, 
pathtype_wf, 
cubical-type-cumulativity2, 
cubical_set_cumulativity-i-j, 
cubicalpath-app_wf, 
interval-0_wf, 
interval-1_wf, 
path-type_wf, 
cubical-type_wf, 
cubical_set_wf, 
cubical_type_at_pair_lemma, 
I_cube_wf, 
fset_wf, 
nat_wf, 
cubical_type_ap_morph_pair_lemma, 
names-hom_wf, 
istype-cubical-type-at, 
cube-set-restriction_wf, 
cubical-type-ap-morph_wf, 
nh-id_wf, 
dM0_wf, 
cubical-term-at_wf, 
subtype-respects-equality, 
cubical-type-at_wf, 
subtype_rel-equal, 
cube-set-restriction-id, 
dM1_wf, 
squash_wf, 
true_wf, 
equal_wf, 
istype-universe, 
subtype_rel_self, 
interval-type_wf, 
path-type-subtype, 
cubical-path-app-0, 
cubical-path-app-1
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation_alt, 
introduction, 
cut, 
independent_pairFormation, 
lambdaEquality_alt, 
setIsType, 
universeIsType, 
thin, 
instantiate, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
hypothesisEquality, 
applyEquality, 
hypothesis, 
sqequalRule, 
productIsType, 
equalityIstype, 
because_Cache, 
productElimination, 
independent_pairEquality, 
axiomEquality, 
inhabitedIsType, 
isect_memberEquality_alt, 
isectIsTypeImplies, 
setElimination, 
rename, 
dependent_set_memberEquality_alt, 
dependent_functionElimination, 
Error :memTop, 
functionExtensionality, 
lambdaFormation_alt, 
functionIsType, 
independent_isectElimination, 
imageElimination, 
natural_numberEquality, 
imageMemberEquality, 
baseClosed, 
independent_functionElimination, 
equalityTransitivity, 
equalitySymmetry, 
hyp_replacement, 
universeEquality, 
applyLambdaEquality
Latex:
\mforall{}[X:j\mvdash{}].  \mforall{}[A:\{X  \mvdash{}  \_\}].  \mforall{}[a,b:\{X  \mvdash{}  \_:A\}].
    \{t:\{X  \mvdash{}  \_:Path(A)\}|  (t  @  0(\mBbbI{})  =  a)  \mwedge{}  (t  @  1(\mBbbI{})  =  b)\}    \mequiv{}  \{X  \mvdash{}  \_:(Path\_A  a  b)\}
Date html generated:
2020_05_20-PM-03_17_17
Last ObjectModification:
2020_04_06-PM-06_36_07
Theory : cubical!type!theory
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