Nuprl Lemma : presheaf-app-id-fun
∀[C:SmallCategory]. ∀[X:ps_context{j:l}(C)]. ∀[A:{X ⊢ _}]. ∀[u:{X ⊢ _:A}].  (app(presheaf-id-fun(X); u) = u ∈ {X ⊢ _:A})
Proof
Definitions occuring in Statement : 
presheaf-app: app(w; u), 
presheaf-id-fun: presheaf-id-fun(X), 
presheaf-term: {X ⊢ _:A}, 
presheaf-type: {X ⊢ _}, 
ps_context: __⊢, 
uall: ∀[x:A]. B[x], 
equal: s = t ∈ T, 
small-category: SmallCategory
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x], 
member: t ∈ T, 
presheaf-id-fun: presheaf-id-fun(X), 
presheaf-lam: presheaf-lam(X;b), 
subtype_rel: A ⊆r B, 
prop: ℙ, 
squash: ↓T, 
true: True, 
uimplies: b supposing a, 
guard: {T}, 
iff: P ⇐⇒ Q, 
and: P ∧ Q, 
rev_implies: P ⇐ Q, 
implies: P ⇒ Q, 
all: ∀x:A. B[x]
Lemmas referenced : 
presheaf-beta, 
pscm-ap-type_wf, 
ps_context_cumulativity2, 
small-category-cumulativity-2, 
psc-adjoin_wf, 
presheaf-type-cumulativity2, 
psc-fst_wf, 
psc-snd_wf, 
presheaf-term_wf, 
presheaf-type_wf, 
ps_context_wf, 
small-category_wf, 
equal_wf, 
squash_wf, 
true_wf, 
istype-universe, 
pscm-ap-type-fst-id-adjoin, 
iff_weakening_equal, 
subtype_rel-equal, 
pscm-id-adjoin_wf, 
subtype_rel_self, 
ps-cc_snd_csm_id_adjoin_lemma, 
pscm-ap-id-term
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation_alt, 
introduction, 
cut, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
hypothesisEquality, 
instantiate, 
applyEquality, 
hypothesis, 
sqequalRule, 
because_Cache, 
universeIsType, 
isect_memberEquality_alt, 
axiomEquality, 
isectIsTypeImplies, 
inhabitedIsType, 
hyp_replacement, 
equalitySymmetry, 
lambdaEquality_alt, 
imageElimination, 
equalityTransitivity, 
universeEquality, 
Error :memTop, 
natural_numberEquality, 
imageMemberEquality, 
baseClosed, 
independent_isectElimination, 
productElimination, 
independent_functionElimination, 
dependent_functionElimination
Latex:
\mforall{}[C:SmallCategory].  \mforall{}[X:ps\_context\{j:l\}(C)].  \mforall{}[A:\{X  \mvdash{}  \_\}].  \mforall{}[u:\{X  \mvdash{}  \_:A\}].
    (app(presheaf-id-fun(X);  u)  =  u)
Date html generated:
2020_05_20-PM-01_33_56
Last ObjectModification:
2020_04_03-AM-01_06_33
Theory : presheaf!models!of!type!theory
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