Nuprl Lemma : paths-are-refl-iff
∀[X:j⊢]. ∀[A:{X ⊢ _}].
  uiff(∀Z:j⊢. ∀s:Z j⟶ X. ∀p:{Z ⊢ _:Path((A)s)}.  (p = refl(p @ 0(𝕀)) ∈ {Z ⊢ _:Path((A)s)});∀Z:j⊢. ∀s:Z j⟶ X.
                                                                                            ∀p:{Z ⊢ _:Path((A)s)}.
                                                                                              ∀[x,y:{Z ⊢ _:𝕀}].
                                                                                                (p @ x
                                                                                                = p @ y
                                                                                                ∈ {Z ⊢ _:(A)s}))
Proof
Definitions occuring in Statement : 
cubical-refl: refl(a)
, 
cubicalpath-app: pth @ r
, 
pathtype: Path(A)
, 
interval-0: 0(𝕀)
, 
interval-type: 𝕀
, 
cubical-term: {X ⊢ _:A}
, 
csm-ap-type: (AF)s
, 
cubical-type: {X ⊢ _}
, 
cube_set_map: A ⟶ B
, 
cubical_set: CubicalSet
, 
uiff: uiff(P;Q)
, 
uall: ∀[x:A]. B[x]
, 
all: ∀x:A. B[x]
, 
equal: s = t ∈ T
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
uiff: uiff(P;Q)
, 
and: P ∧ Q
, 
uimplies: b supposing a
, 
member: t ∈ T
, 
all: ∀x:A. B[x]
, 
subtype_rel: A ⊆r B
, 
implies: P 
⇒ Q
, 
true: True
, 
rev_implies: P 
⇐ Q
, 
squash: ↓T
, 
prop: ℙ
, 
guard: {T}
, 
iff: P 
⇐⇒ Q
, 
cubical-path-app: pth @ r
, 
cubical-type: {X ⊢ _}
, 
csm-ap-type: (AF)s
, 
cc-fst: p
, 
interval-type: 𝕀
, 
csm-comp: G o F
, 
csm-ap: (s)x
, 
compose: f o g
, 
cc-snd: q
, 
constant-cubical-type: (X)
, 
cube_set_map: A ⟶ B
, 
psc_map: A ⟶ B
, 
nat-trans: nat-trans(C;D;F;G)
, 
cat-ob: cat-ob(C)
, 
pi1: fst(t)
, 
op-cat: op-cat(C)
, 
spreadn: spread4, 
cube-cat: CubeCat
, 
fset: fset(T)
, 
quotient: x,y:A//B[x; y]
, 
cat-arrow: cat-arrow(C)
, 
pi2: snd(t)
, 
type-cat: TypeCat
, 
names-hom: I ⟶ J
, 
cat-comp: cat-comp(C)
Lemmas referenced : 
cube_set_map_wf, 
cubical-term_wf, 
pathtype_wf, 
csm-ap-type_wf, 
cubical-type-cumulativity2, 
cubical_set_cumulativity-i-j, 
cubical-refl_wf, 
cubicalpath-app_wf, 
interval-0_wf, 
path-type-subtype, 
interval-type_wf, 
cubical-type_wf, 
cubical_set_wf, 
equal_wf, 
squash_wf, 
true_wf, 
istype-universe, 
subtype_rel_self, 
iff_weakening_equal, 
refl-path-app, 
term-to-pathtype-eta, 
term-to-pathtype_wf, 
csm-pathtype, 
cube-context-adjoin_wf, 
cc-fst_wf, 
csm-comp_wf, 
csm-ap-term_wf, 
equal_functionality_wrt_subtype_rel2, 
cc-snd_wf, 
csm-cubical-refl, 
cubical-path-app_wf, 
csm-cubicalpath-app, 
csm-interval-0, 
subset-cubical-term2, 
sub_cubical_set_self
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation_alt, 
independent_pairFormation, 
introduction, 
cut, 
sqequalRule, 
sqequalHypSubstitution, 
lambdaEquality_alt, 
dependent_functionElimination, 
thin, 
hypothesisEquality, 
isect_memberEquality_alt, 
isectElimination, 
axiomEquality, 
hypothesis, 
isectIsTypeImplies, 
inhabitedIsType, 
functionIsTypeImplies, 
functionIsType, 
universeIsType, 
extract_by_obid, 
instantiate, 
applyEquality, 
equalityIstype, 
because_Cache, 
isectIsType, 
lambdaFormation_alt, 
equalityTransitivity, 
equalitySymmetry, 
independent_functionElimination, 
natural_numberEquality, 
imageElimination, 
universeEquality, 
imageMemberEquality, 
baseClosed, 
independent_isectElimination, 
productElimination, 
applyLambdaEquality, 
setElimination, 
rename, 
cumulativity, 
hyp_replacement, 
Error :memTop
Latex:
\mforall{}[X:j\mvdash{}].  \mforall{}[A:\{X  \mvdash{}  \_\}].
    uiff(\mforall{}Z:j\mvdash{}.  \mforall{}s:Z  j{}\mrightarrow{}  X.  \mforall{}p:\{Z  \mvdash{}  \_:Path((A)s)\}.    (p  =  refl(p  @  0(\mBbbI{})));\mforall{}Z:j\mvdash{}.  \mforall{}s:Z  j{}\mrightarrow{}  X.
                                                                                                                                              \mforall{}p:\{Z  \mvdash{}  \_:Path((A)s)\}.
                                                                                                                                                  \mforall{}[x,y:\{Z  \mvdash{}  \_:\mBbbI{}\}].
                                                                                                                                                      (p  @  x  =  p  @  y))
Date html generated:
2020_05_20-PM-03_43_53
Last ObjectModification:
2020_04_07-PM-06_01_45
Theory : cubical!type!theory
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