Nuprl Lemma : presheaf-term-at-comp
∀C:SmallCategory. ∀Gamma:ps_context{j:l}(C). ∀T:{Gamma ⊢ _}. ∀t:{Gamma ⊢ _:T}. ∀I:cat-ob(C). ∀rho:Gamma(I).
∀J:cat-ob(C). ∀f:cat-arrow(C) J I. ∀K:cat-ob(C). ∀g:cat-arrow(C) K J.
  (t(cat-comp(C) K J I g f(rho)) = t(g(f(rho))) ∈ T(g(f(rho))))
Proof
Definitions occuring in Statement : 
presheaf-term-at: u(a)
, 
presheaf-term: {X ⊢ _:A}
, 
presheaf-type-at: A(a)
, 
presheaf-type: {X ⊢ _}
, 
psc-restriction: f(s)
, 
I_set: A(I)
, 
ps_context: __⊢
, 
all: ∀x:A. B[x]
, 
apply: f a
, 
equal: s = t ∈ T
, 
cat-comp: cat-comp(C)
, 
cat-arrow: cat-arrow(C)
, 
cat-ob: cat-ob(C)
, 
small-category: SmallCategory
Definitions unfolded in proof : 
all: ∀x:A. B[x]
, 
member: t ∈ T
, 
squash: ↓T
, 
uall: ∀[x:A]. B[x]
, 
prop: ℙ
, 
subtype_rel: A ⊆r B
, 
uimplies: b supposing a
, 
true: True
, 
guard: {T}
, 
iff: P 
⇐⇒ Q
, 
and: P ∧ Q
, 
rev_implies: P 
⇐ Q
, 
implies: P 
⇒ Q
Lemmas referenced : 
equal_wf, 
squash_wf, 
true_wf, 
istype-universe, 
presheaf-type-at_wf, 
psc-restriction_wf, 
presheaf-term-at_wf, 
cat-comp_wf, 
subtype_rel-equal, 
psc-restriction-comp, 
I_set_wf, 
cat-ob_wf, 
presheaf-term_wf, 
presheaf-type_wf, 
ps_context_wf, 
small-category-cumulativity-2, 
small-category_wf, 
subtype_rel_self, 
iff_weakening_equal, 
cat-arrow_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation_alt, 
cut, 
applyEquality, 
thin, 
lambdaEquality_alt, 
sqequalHypSubstitution, 
imageElimination, 
introduction, 
extract_by_obid, 
isectElimination, 
hypothesisEquality, 
equalityTransitivity, 
hypothesis, 
equalitySymmetry, 
universeIsType, 
instantiate, 
universeEquality, 
independent_isectElimination, 
because_Cache, 
dependent_functionElimination, 
natural_numberEquality, 
sqequalRule, 
imageMemberEquality, 
baseClosed, 
productElimination, 
independent_functionElimination
Latex:
\mforall{}C:SmallCategory.  \mforall{}Gamma:ps\_context\{j:l\}(C).  \mforall{}T:\{Gamma  \mvdash{}  \_\}.  \mforall{}t:\{Gamma  \mvdash{}  \_:T\}.  \mforall{}I:cat-ob(C).
\mforall{}rho:Gamma(I).  \mforall{}J:cat-ob(C).  \mforall{}f:cat-arrow(C)  J  I.  \mforall{}K:cat-ob(C).  \mforall{}g:cat-arrow(C)  K  J.
    (t(cat-comp(C)  K  J  I  g  f(rho))  =  t(g(f(rho))))
Date html generated:
2020_05_20-PM-01_34_56
Last ObjectModification:
2020_04_02-PM-06_34_24
Theory : presheaf!models!of!type!theory
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