Nuprl Lemma : presheaf-beta
∀[C:SmallCategory]. ∀[X:ps_context{j:l}(C)]. ∀[A:{X ⊢ _}]. ∀[B:{X.A ⊢ _}]. ∀[b:{X.A ⊢ _:B}]. ∀[u:{X ⊢ _:A}].
  (app((λb); u) = (b)[u] ∈ {X ⊢ _:(B)[u]})
Proof
Definitions occuring in Statement : 
presheaf-app: app(w; u)
, 
presheaf-lambda: (λb)
, 
pscm-id-adjoin: [u]
, 
psc-adjoin: X.A
, 
pscm-ap-term: (t)s
, 
presheaf-term: {X ⊢ _:A}
, 
pscm-ap-type: (AF)s
, 
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
, 
subtype_rel: A ⊆r B
, 
presheaf-term: {X ⊢ _:A}
, 
uimplies: b supposing a
, 
presheaf-lambda: (λb)
, 
presheaf-app: app(w; u)
, 
pscm-ap-term: (t)s
, 
pscm-ap: (s)x
, 
pscm-id-adjoin: [u]
, 
pscm-id: 1(X)
, 
pscm-adjoin: (s;u)
, 
psc-adjoin-set: (v;u)
, 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
presheaf-type: {X ⊢ _}
, 
presheaf-type-at: A(a)
, 
pi1: fst(t)
, 
squash: ↓T
, 
prop: ℙ
, 
true: True
, 
guard: {T}
, 
iff: P 
⇐⇒ Q
, 
and: P ∧ Q
, 
rev_implies: P 
⇐ Q
Lemmas referenced : 
presheaf-term-equal, 
pscm-ap-type_wf, 
psc-adjoin_wf, 
ps_context_cumulativity2, 
presheaf-type-cumulativity2, 
pscm-id-adjoin_wf, 
pscm-ap-term_wf, 
presheaf-app_wf, 
presheaf-lambda_wf, 
pscm-ap-type-at, 
I_set_wf, 
presheaf-term_wf, 
presheaf-term_wf2, 
small-category-cumulativity-2, 
presheaf-type_wf, 
ps_context_wf, 
small-category_wf, 
equal_wf, 
squash_wf, 
true_wf, 
istype-universe, 
psc-adjoin-set_wf, 
subtype_rel_self, 
psc-restriction-id, 
subtype_rel-equal, 
presheaf-type-at_wf, 
psc-restriction_wf, 
cat-id_wf, 
presheaf_type_at_pair_lemma, 
cat-ob_wf, 
iff_weakening_equal
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation_alt, 
introduction, 
cut, 
equalitySymmetry, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
hypothesisEquality, 
instantiate, 
applyEquality, 
because_Cache, 
hypothesis, 
sqequalRule, 
lambdaEquality_alt, 
setElimination, 
rename, 
inhabitedIsType, 
equalityTransitivity, 
independent_isectElimination, 
Error :memTop, 
functionExtensionality_alt, 
lambdaFormation_alt, 
equalityIstype, 
dependent_functionElimination, 
independent_functionElimination, 
universeIsType, 
isect_memberEquality_alt, 
axiomEquality, 
isectIsTypeImplies, 
productElimination, 
imageElimination, 
universeEquality, 
imageMemberEquality, 
baseClosed, 
natural_numberEquality
Latex:
\mforall{}[C:SmallCategory].  \mforall{}[X:ps\_context\{j:l\}(C)].  \mforall{}[A:\{X  \mvdash{}  \_\}].  \mforall{}[B:\{X.A  \mvdash{}  \_\}].  \mforall{}[b:\{X.A  \mvdash{}  \_:B\}].
\mforall{}[u:\{X  \mvdash{}  \_:A\}].
    (app((\mlambda{}b);  u)  =  (b)[u])
Date html generated:
2020_05_20-PM-01_33_51
Last ObjectModification:
2020_04_02-PM-06_33_28
Theory : presheaf!models!of!type!theory
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