Nuprl Lemma : ps_context-ext
∀[C:SmallCategory]
  {FM:F:cat-ob(C) ⟶ 𝕌{j'} × (I:cat-ob(C) ⟶ J:cat-ob(C) ⟶ (cat-arrow(C) J I) ⟶ (F I) ⟶ (F J))| 
   let F,M = FM 
   in (∀I:cat-ob(C). ∀s:FM(I).  (cat-id(C) I(s) = s ∈ FM(I)))
      ∧ (∀I,J,K:cat-ob(C). ∀f:cat-arrow(C) J I. ∀g:cat-arrow(C) K J. ∀s:FM(I).
           (cat-comp(C) K J I g f(s) = g(f(s)) ∈ FM(K)))}  ≡ ps_context{j:l}(C)
Proof
Definitions occuring in Statement : 
psc-restriction: f(s), 
I_set: A(I), 
ps_context: __⊢, 
ext-eq: A ≡ B, 
uall: ∀[x:A]. B[x], 
all: ∀x:A. B[x], 
and: P ∧ Q, 
set: {x:A| B[x]} , 
apply: f a, 
function: x:A ⟶ B[x], 
spread: spread def, 
product: x:A × B[x], 
universe: Type, 
equal: s = t ∈ T, 
cat-comp: cat-comp(C), 
cat-id: cat-id(C), 
cat-arrow: cat-arrow(C), 
cat-ob: cat-ob(C), 
small-category: SmallCategory
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x], 
member: t ∈ T, 
sq_stable: SqStable(P), 
implies: P ⇒ Q, 
squash: ↓T, 
all: ∀x:A. B[x], 
and: P ∧ Q, 
prop: ℙ, 
subtype_rel: A ⊆r B, 
small-category: SmallCategory, 
spreadn: spread4, 
ps_context: __⊢, 
cat-arrow: cat-arrow(C), 
cat-ob: cat-ob(C), 
pi1: fst(t), 
pi2: snd(t), 
type-cat: TypeCat, 
op-cat: op-cat(C), 
cat-functor: Functor(C1;C2), 
compose: f o g, 
psc-restriction: f(s), 
I_set: A(I), 
functor-ob: ob(F), 
ext-eq: A ≡ B, 
cand: A c∧ B, 
guard: {T}, 
true: True, 
uimplies: b supposing a, 
iff: P ⇐⇒ Q, 
rev_implies: P ⇐ Q
Lemmas referenced : 
sq_stable__ext-eq, 
small-category_wf, 
cat-ob_wf, 
cat-arrow_wf, 
I_set_pair_redex_lemma, 
psc_restriction_pair_lemma, 
equal_wf, 
cat-id_wf, 
cat-comp_wf, 
ps_context_wf, 
small-category-cumulativity-2, 
cat_id_tuple_lemma, 
cat_comp_tuple_lemma, 
cat_ob_pair_lemma, 
cat_arrow_triple_lemma, 
istype-universe, 
iff_weakening_equal, 
squash_wf, 
true_wf, 
subtype_rel_self
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation_alt, 
cut, 
thin, 
instantiate, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
hypothesis, 
independent_functionElimination, 
sqequalRule, 
imageMemberEquality, 
hypothesisEquality, 
baseClosed, 
imageElimination, 
universeIsType, 
setEquality, 
productEquality, 
functionEquality, 
cumulativity, 
universeEquality, 
applyEquality, 
productElimination, 
dependent_functionElimination, 
Error :memTop, 
setElimination, 
rename, 
independent_pairFormation, 
lambdaEquality_alt, 
setIsType, 
productIsType, 
functionIsType, 
because_Cache, 
equalityIstype, 
dependent_set_memberEquality_alt, 
dependent_pairEquality_alt, 
inhabitedIsType, 
lambdaFormation_alt, 
functionExtensionality_alt, 
natural_numberEquality, 
equalityTransitivity, 
equalitySymmetry, 
independent_isectElimination
Latex:
\mforall{}[C:SmallCategory]
    \{FM:F:cat-ob(C)  {}\mrightarrow{}  \mBbbU{}\{j'\}  \mtimes{}  (I:cat-ob(C)  {}\mrightarrow{}  J:cat-ob(C)  {}\mrightarrow{}  (cat-arrow(C)  J  I)  {}\mrightarrow{}  (F  I)  {}\mrightarrow{}  (F  J))| 
      let  F,M  =  FM 
      in  (\mforall{}I:cat-ob(C).  \mforall{}s:FM(I).    (cat-id(C)  I(s)  =  s))
            \mwedge{}  (\mforall{}I,J,K:cat-ob(C).  \mforall{}f:cat-arrow(C)  J  I.  \mforall{}g:cat-arrow(C)  K  J.  \mforall{}s:FM(I).
                      (cat-comp(C)  K  J  I  g  f(s)  =  g(f(s))))\}    \mequiv{}  ps\_context\{j:l\}(C)
Date html generated:
2020_05_20-PM-01_23_22
Last ObjectModification:
2020_03_31-PM-07_30_09
Theory : presheaf!models!of!type!theory
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