Nuprl Lemma : presheaf-sigma_wf
∀[C:SmallCategory]. ∀[X:ps_context{j:l}(C)]. ∀[A:{X ⊢ _}]. ∀[B:{X.A ⊢ _}].  (Σ A B ∈ X ⊢ )
Proof
Definitions occuring in Statement : 
presheaf-sigma: Σ A B
, 
psc-adjoin: X.A
, 
presheaf-type: {X ⊢ _}
, 
ps_context: __⊢
, 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
small-category: SmallCategory
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
presheaf-sigma: Σ A B
, 
presheaf-type: {X ⊢ _}
, 
subtype_rel: A ⊆r B
, 
all: ∀x:A. B[x]
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
psc-restriction: f(s)
, 
pi2: snd(t)
, 
psc-adjoin: X.A
, 
psc-adjoin-set: (v;u)
, 
pi1: fst(t)
, 
and: P ∧ Q
, 
cand: A c∧ B
, 
squash: ↓T
, 
prop: ℙ
, 
true: True
, 
uimplies: b supposing a
, 
guard: {T}
, 
iff: P 
⇐⇒ Q
, 
rev_implies: P 
⇐ Q
, 
implies: P 
⇒ Q
Lemmas referenced : 
presheaf-type-at_wf, 
psc-adjoin_wf, 
ps_context_cumulativity2, 
presheaf-type-cumulativity2, 
psc-adjoin-set_wf, 
I_set_wf, 
cat-ob_wf, 
presheaf-type-ap-morph_wf, 
pi1_wf_top, 
pi2_wf, 
subtype_rel_self, 
small-category-cumulativity-2, 
psc-restriction_wf, 
cat-arrow_wf, 
equal_wf, 
squash_wf, 
true_wf, 
istype-universe, 
cat-comp_wf, 
presheaf-type-ap-morph-comp, 
iff_weakening_equal, 
presheaf-type-ap-morph-comp-eq, 
psc-adjoin-set-restriction, 
cat-id_wf, 
subtype_rel-equal, 
psc-restriction-id, 
psc-restriction-comp, 
presheaf-type_wf, 
ps_context_wf, 
small-category_wf, 
presheaf-type-ap-morph-id
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation_alt, 
introduction, 
cut, 
dependent_set_memberEquality_alt, 
dependent_pairEquality_alt, 
lambdaEquality_alt, 
productEquality, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
hypothesisEquality, 
hypothesis, 
instantiate, 
applyEquality, 
because_Cache, 
sqequalRule, 
dependent_functionElimination, 
universeIsType, 
productElimination, 
independent_pairEquality, 
Error :memTop, 
productIsType, 
inhabitedIsType, 
functionIsType, 
lambdaFormation_alt, 
independent_pairFormation, 
imageElimination, 
equalityTransitivity, 
equalitySymmetry, 
universeEquality, 
natural_numberEquality, 
imageMemberEquality, 
baseClosed, 
independent_isectElimination, 
independent_functionElimination, 
equalityIstype, 
axiomEquality, 
isect_memberEquality_alt, 
isectIsTypeImplies
Latex:
\mforall{}[C:SmallCategory].  \mforall{}[X:ps\_context\{j:l\}(C)].  \mforall{}[A:\{X  \mvdash{}  \_\}].  \mforall{}[B:\{X.A  \mvdash{}  \_\}].    (\mSigma{}  A  B  \mmember{}  X  \mvdash{}  )
Date html generated:
2020_05_20-PM-01_31_23
Last ObjectModification:
2020_04_02-PM-03_03_10
Theory : presheaf!models!of!type!theory
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