Nuprl Lemma : extend-to-contraction_wf
∀Gamma:j⊢. ∀A:{Gamma ⊢ _}. ∀ext:Gamma +⊢ Extension(A).
  (extend-to-contraction(Gamma;A;ext) ∈ {Gamma ⊢ _:Contractible(A)})
Proof
Definitions occuring in Statement : 
extend-to-contraction: extend-to-contraction(Gamma;A;ext)
, 
uniform-extend: uniform-extend{i:l}(Gamma; A)
, 
contractible-type: Contractible(A)
, 
cubical-term: {X ⊢ _:A}
, 
cubical-type: {X ⊢ _}
, 
cubical_set: CubicalSet
, 
all: ∀x:A. B[x]
, 
member: t ∈ T
Definitions unfolded in proof : 
all: ∀x:A. B[x]
, 
member: t ∈ T
, 
uniform-extend: uniform-extend{i:l}(Gamma; A)
, 
extension-fun: extension-fun{i:l}(Gamma;A)
, 
uall: ∀[x:A]. B[x]
, 
subtype_rel: A ⊆r B
, 
extend-to-contraction: extend-to-contraction(Gamma;A;ext)
, 
constrained-cubical-term: {Gamma ⊢ _:A[phi |⟶ t]}
, 
uimplies: b supposing a
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
cubical-type: {X ⊢ _}
, 
cc-snd: q
, 
interval-type: 𝕀
, 
cc-fst: p
, 
csm-ap-type: (AF)s
, 
constant-cubical-type: (X)
, 
csm-comp: G o F
, 
compose: f o g
, 
csm-ap: (s)x
, 
squash: ↓T
, 
prop: ℙ
, 
true: True
, 
uniform-extension-fun: uniform-extension-fun{i:l}(Gamma;A;ext)
, 
pi1: fst(t)
, 
csm-adjoin: (s;u)
, 
csm-id: 1(X)
, 
csm-id-adjoin: [u]
, 
interval-0: 0(𝕀)
, 
implies: P 
⇒ Q
, 
interval-1: 1(𝕀)
, 
csm-ap-term: (t)s
, 
pi2: snd(t)
, 
guard: {T}
, 
iff: P 
⇐⇒ Q
, 
and: P ∧ Q
, 
rev_implies: P 
⇐ Q
Lemmas referenced : 
csm-ap-term_wf, 
cube-context-adjoin_wf, 
cubical-type-cumulativity2, 
cubical_set_cumulativity-i-j, 
interval-type_wf, 
csm-ap-type_wf, 
cc-fst_wf, 
cc-fst_wf_interval, 
cc-snd_wf, 
contr-witness_wf, 
csm-id_wf, 
face-0_wf, 
empty-context-subset-lemma3, 
subtype_rel_set, 
cubical-term-eqcd, 
equal-wf-base-T, 
thin-context-subset, 
context-subset_wf, 
istype-cubical-term, 
subset-cubical-term2, 
sub_cubical_set_self, 
csm-ap-id-type, 
term-to-path_wf, 
csm-comp_wf, 
face-one_wf, 
context-subset-is-subset, 
context-subset-term-subtype, 
path-type_wf, 
squash_wf, 
true_wf, 
uniform-extend_wf, 
cubical-type_wf, 
cubical_set_wf, 
csm-id-adjoin_wf-interval-0, 
istype-universe, 
equal_wf, 
csm-face-0, 
face-one-interval-0, 
csm-interval-0, 
cc_snd_csm_id_adjoin_lemma, 
csm-face-one, 
csm_id_adjoin_fst_term_lemma, 
context-subset-map, 
csm-id-adjoin_wf-interval-1, 
interval-1_wf, 
subset-cubical-term, 
context-1-subset, 
face-one-interval-1, 
sub_cubical_set_wf, 
face-type_wf, 
iff_weakening_equal
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation_alt, 
cut, 
sqequalHypSubstitution, 
setElimination, 
thin, 
rename, 
instantiate, 
introduction, 
extract_by_obid, 
isectElimination, 
hypothesisEquality, 
applyEquality, 
because_Cache, 
hypothesis, 
sqequalRule, 
Error :memTop, 
equalityTransitivity, 
equalitySymmetry, 
independent_isectElimination, 
lambdaEquality_alt, 
baseClosed, 
dependent_functionElimination, 
productElimination, 
imageElimination, 
universeIsType, 
inhabitedIsType, 
natural_numberEquality, 
imageMemberEquality, 
hyp_replacement, 
universeEquality, 
applyLambdaEquality, 
equalityIstype, 
independent_functionElimination
Latex:
\mforall{}Gamma:j\mvdash{}.  \mforall{}A:\{Gamma  \mvdash{}  \_\}.  \mforall{}ext:Gamma  +\mvdash{}  Extension(A).
    (extend-to-contraction(Gamma;A;ext)  \mmember{}  \{Gamma  \mvdash{}  \_:Contractible(A)\})
Date html generated:
2020_05_20-PM-05_22_45
Last ObjectModification:
2020_05_02-PM-03_25_05
Theory : cubical!type!theory
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