Nuprl Lemma : presheaf-type-iso-inverse2
∀[C:SmallCategory]. ∀[X:ps_context{j:l}(C)].
  ((presheaf-type-iso(X) o presheaf-type-rev-iso(X)) = (λx.x) ∈ ({X ⊢ _} ⟶ {X ⊢ _}))
Proof
Definitions occuring in Statement : 
presheaf-type-rev-iso: presheaf-type-rev-iso(X)
, 
presheaf-type-iso: presheaf-type-iso(X)
, 
presheaf-type: {X ⊢ _}
, 
ps_context: __⊢
, 
compose: f o g
, 
uall: ∀[x:A]. B[x]
, 
lambda: λx.A[x]
, 
function: x:A ⟶ B[x]
, 
equal: s = t ∈ T
, 
small-category: SmallCategory
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
compose: f o g
, 
presheaf-type: {X ⊢ _}
, 
presheaf-type-rev-iso: presheaf-type-rev-iso(X)
, 
presheaf-type-iso: presheaf-type-iso(X)
, 
pi1: fst(t)
, 
pi2: snd(t)
, 
mk-presheaf: mk-presheaf, 
all: ∀x:A. B[x]
, 
so_lambda: so_lambda3, 
so_apply: x[s1;s2;s3]
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
subtype_rel: A ⊆r B
, 
and: P ∧ Q
, 
uimplies: b supposing a
, 
squash: ↓T
, 
prop: ℙ
, 
true: True
, 
guard: {T}
, 
iff: P 
⇐⇒ Q
, 
rev_implies: P 
⇐ Q
, 
implies: P 
⇒ Q
Lemmas referenced : 
ob_mk_functor_lemma, 
arrow_mk_functor_lemma, 
I_set_wf, 
cat-ob_wf, 
cat-arrow_wf, 
psc-restriction_wf, 
small-category-cumulativity-2, 
ps_context_cumulativity2, 
cat-id_wf, 
subtype_rel-equal, 
equal_wf, 
squash_wf, 
true_wf, 
istype-universe, 
psc-restriction-id, 
subtype_rel_self, 
iff_weakening_equal, 
cat-comp_wf, 
psc-restriction-comp, 
presheaf-type_wf, 
ps_context_wf, 
small-category_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation_alt, 
introduction, 
cut, 
functionExtensionality, 
sqequalRule, 
equalitySymmetry, 
sqequalHypSubstitution, 
setElimination, 
thin, 
rename, 
dependent_set_memberEquality_alt, 
productElimination, 
extract_by_obid, 
dependent_functionElimination, 
Error :memTop, 
hypothesis, 
dependent_pairEquality_alt, 
applyEquality, 
hypothesisEquality, 
isectElimination, 
because_Cache, 
functionIsType, 
universeIsType, 
instantiate, 
productIsType, 
equalityIstype, 
independent_isectElimination, 
lambdaEquality_alt, 
imageElimination, 
equalityTransitivity, 
universeEquality, 
natural_numberEquality, 
imageMemberEquality, 
baseClosed, 
independent_functionElimination, 
isect_memberEquality_alt, 
axiomEquality, 
isectIsTypeImplies, 
inhabitedIsType
Latex:
\mforall{}[C:SmallCategory].  \mforall{}[X:ps\_context\{j:l\}(C)].
    ((presheaf-type-iso(X)  o  presheaf-type-rev-iso(X))  =  (\mlambda{}x.x))
Date html generated:
2020_05_20-PM-01_25_44
Last ObjectModification:
2020_04_01-AM-11_00_50
Theory : presheaf!models!of!type!theory
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