Nuprl Lemma : contr-witness_wf
∀[X:j⊢]. ∀[A:{X ⊢ _}]. ∀[c:{X ⊢ _:A}]. ∀[p:{X.A ⊢ _:(Path_(A)p (c)p q)}].
  (contr-witness(X;c;p) ∈ {X ⊢ _:Contractible(A)})
Proof
Definitions occuring in Statement : 
contr-witness: contr-witness(X;c;p), 
contractible-type: Contractible(A), 
path-type: (Path_A a b), 
cc-snd: q, 
cc-fst: p, 
cube-context-adjoin: X.A, 
csm-ap-term: (t)s, 
cubical-term: {X ⊢ _:A}, 
csm-ap-type: (AF)s, 
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, 
contr-witness: contr-witness(X;c;p), 
contractible-type: Contractible(A), 
subtype_rel: A ⊆r B, 
squash: ↓T, 
prop: ℙ, 
true: True, 
all: ∀x:A. B[x], 
uimplies: b supposing a, 
guard: {T}, 
iff: P ⇐⇒ Q, 
and: P ∧ Q, 
rev_implies: P ⇐ Q, 
implies: P ⇒ Q, 
cubical-type: {X ⊢ _}, 
cc-snd: q, 
cc-fst: p, 
csm-ap-type: (AF)s, 
csm-id-adjoin: [u], 
csm-comp: G o F, 
csm-ap: (s)x, 
csm-id: 1(X), 
csm-adjoin: (s;u), 
compose: f o g, 
pi1: fst(t), 
csm-ap-term: (t)s, 
pi2: snd(t)
Lemmas referenced : 
cubical-pair_wf, 
cubical-pi_wf, 
cube-context-adjoin_wf, 
cubical_set_cumulativity-i-j, 
cubical-type-cumulativity2, 
csm-ap-type_wf, 
cc-fst_wf, 
path-type_wf, 
csm-ap-term_wf, 
cc-snd_wf, 
cubical-term_wf, 
cubical-type_wf, 
cubical_set_wf, 
squash_wf, 
true_wf, 
cubical-lambda_wf, 
equal_wf, 
istype-universe, 
csm-cubical-pi, 
csm-id-adjoin_wf, 
subtype_rel_self, 
iff_weakening_equal, 
csm_id_adjoin_fst_type_lemma, 
csm-ap-id-type, 
csm-path-type, 
csm-adjoin_wf, 
csm-comp_wf, 
subtype_rel-equal, 
cube_set_map_wf, 
csm-id_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation_alt, 
introduction, 
cut, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
hypothesisEquality, 
instantiate, 
applyEquality, 
hypothesis, 
sqequalRule, 
because_Cache, 
axiomEquality, 
equalityTransitivity, 
equalitySymmetry, 
universeIsType, 
isect_memberEquality_alt, 
isectIsTypeImplies, 
inhabitedIsType, 
lambdaEquality_alt, 
imageElimination, 
natural_numberEquality, 
imageMemberEquality, 
baseClosed, 
hyp_replacement, 
universeEquality, 
dependent_functionElimination, 
independent_isectElimination, 
productElimination, 
independent_functionElimination, 
Error :memTop, 
setElimination, 
rename
Latex:
\mforall{}[X:j\mvdash{}].  \mforall{}[A:\{X  \mvdash{}  \_\}].  \mforall{}[c:\{X  \mvdash{}  \_:A\}].  \mforall{}[p:\{X.A  \mvdash{}  \_:(Path\_(A)p  (c)p  q)\}].
    (contr-witness(X;c;p)  \mmember{}  \{X  \mvdash{}  \_:Contractible(A)\})
Date html generated:
2020_05_20-PM-03_23_30
Last ObjectModification:
2020_04_07-PM-03_49_59
Theory : cubical!type!theory
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