Nuprl Lemma : discrete-pair-inv-property
∀[A:Type]. ∀[B:A ⟶ Type]. ∀[X:j⊢]. ∀[b:{X ⊢ _:discr(a:A × B[a])}].
  (discrete-pair(discrete-pair-inv(X;b)) = b ∈ {X ⊢ _:discr(a:A × B[a])})
Proof
Definitions occuring in Statement : 
discrete-pair-inv: discrete-pair-inv(X;b)
, 
discrete-pair: discrete-pair(p)
, 
discrete-cubical-type: discr(T)
, 
cubical-term: {X ⊢ _:A}
, 
cubical_set: CubicalSet
, 
uall: ∀[x:A]. B[x]
, 
so_apply: x[s]
, 
function: x:A ⟶ B[x]
, 
product: x:A × B[x]
, 
universe: Type
, 
equal: s = t ∈ T
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
discrete-pair-inv: discrete-pair-inv(X;b)
, 
so_apply: x[s]
, 
uimplies: b supposing a
, 
discrete-pair: discrete-pair(p)
, 
discrete-cubical-type: discr(T)
, 
all: ∀x:A. B[x]
, 
cubical-snd: p.2
, 
cubical-fst: p.1
, 
cubical-term-at: u(a)
, 
cubical-pair: cubical-pair(u;v)
, 
pi1: fst(t)
, 
pi2: snd(t)
, 
implies: P 
⇒ Q
Lemmas referenced : 
I_cube_wf, 
fset_wf, 
nat_wf, 
cubical-term-equal, 
discrete-cubical-type_wf, 
cubical-term_wf, 
cubical_set_wf, 
istype-universe, 
cubical_type_at_pair_lemma, 
cubical-term-at_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation_alt, 
introduction, 
cut, 
equalitySymmetry, 
functionExtensionality, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
hypothesisEquality, 
hypothesis, 
productEquality, 
applyEquality, 
equalityTransitivity, 
independent_isectElimination, 
universeIsType, 
instantiate, 
cumulativity, 
sqequalRule, 
isect_memberEquality_alt, 
axiomEquality, 
isectIsTypeImplies, 
inhabitedIsType, 
functionIsType, 
universeEquality, 
dependent_functionElimination, 
Error :memTop, 
lambdaFormation_alt, 
productElimination, 
dependent_pairEquality_alt, 
equalityIstype, 
independent_functionElimination
Latex:
\mforall{}[A:Type].  \mforall{}[B:A  {}\mrightarrow{}  Type].  \mforall{}[X:j\mvdash{}].  \mforall{}[b:\{X  \mvdash{}  \_:discr(a:A  \mtimes{}  B[a])\}].
    (discrete-pair(discrete-pair-inv(X;b))  =  b)
Date html generated:
2020_05_20-PM-03_40_58
Last ObjectModification:
2020_04_06-PM-07_12_28
Theory : cubical!type!theory
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