Nuprl Lemma : equiv-discrete-type
∀A,B:Type. ∀f:A ⟶ B.  (Bij(A;B;f) 
⇒ (∀X:j⊢. {X ⊢ _:Equiv(discr(A);discr(B))}))
Proof
Definitions occuring in Statement : 
cubical-equiv: Equiv(T;A)
, 
discrete-cubical-type: discr(T)
, 
cubical-term: {X ⊢ _:A}
, 
cubical_set: CubicalSet
, 
biject: Bij(A;B;f)
, 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
function: x:A ⟶ B[x]
, 
universe: Type
Definitions unfolded in proof : 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
exists: ∃x:A. B[x]
, 
and: P ∧ Q
, 
uimplies: b supposing a
, 
subtype_rel: A ⊆r B
, 
prop: ℙ
Lemmas referenced : 
biject-inverse, 
bijection-equiv_wf, 
cubical_set_cumulativity-i-j, 
cubical_set_wf, 
biject_wf, 
istype-universe
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation_alt, 
cut, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
hypothesisEquality, 
independent_functionElimination, 
hypothesis, 
productElimination, 
instantiate, 
cumulativity, 
independent_isectElimination, 
applyEquality, 
sqequalRule, 
universeIsType, 
functionIsType, 
inhabitedIsType, 
universeEquality
Latex:
\mforall{}A,B:Type.  \mforall{}f:A  {}\mrightarrow{}  B.    (Bij(A;B;f)  {}\mRightarrow{}  (\mforall{}X:j\mvdash{}.  \{X  \mvdash{}  \_:Equiv(discr(A);discr(B))\}))
Date html generated:
2020_05_20-PM-03_43_05
Last ObjectModification:
2020_04_06-PM-07_14_26
Theory : cubical!type!theory
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