Nuprl Lemma : ps-sigma-unelim-elim
∀[C:SmallCategory]. ∀[X:ps_context{j:l}(C)]. ∀[A:{X ⊢ _}]. ∀[B:{X.A ⊢ _}].
  (SigmaElim o SigmaUnElim = 1(X.A.B) ∈ psc_map{[i | j]:l}(C; X.A.B; X.A.B))
Proof
Definitions occuring in Statement : 
sigma-unelim-pscm: SigmaUnElim
, 
sigma-elim-pscm: SigmaElim
, 
presheaf-sigma: Σ A B
, 
psc-adjoin: X.A
, 
presheaf-type: {X ⊢ _}
, 
pscm-id: 1(X)
, 
pscm-comp: G o F
, 
psc_map: A ⟶ B
, 
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
, 
psc-adjoin: X.A
, 
all: ∀x:A. B[x]
, 
pscm-id: 1(X)
, 
sigma-elim-pscm: SigmaElim
, 
sigma-unelim-pscm: SigmaUnElim
, 
psc-adjoin-set: (v;u)
, 
pscm-comp: G o F
, 
compose: f o g
, 
spreadn: spread3, 
uimplies: b supposing a
, 
I_set: A(I)
, 
functor-ob: ob(F)
, 
pi1: fst(t)
Lemmas referenced : 
presheaf-type_wf, 
psc-adjoin_wf, 
small-category-cumulativity-2, 
ps_context_cumulativity2, 
presheaf-type-cumulativity2, 
ps_context_wf, 
small-category_wf, 
pscm-comp_wf, 
presheaf-sigma_wf, 
sigma-unelim-pscm_wf, 
sigma-elim-pscm_wf, 
pscm-id_wf, 
I_set_pair_redex_lemma, 
psc_restriction_pair_lemma, 
I_set_wf, 
cat-ob_wf, 
pscm-equal, 
presheaf-type-at_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation_alt, 
introduction, 
cut, 
hypothesis, 
universeIsType, 
thin, 
instantiate, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
hypothesisEquality, 
applyEquality, 
sqequalRule, 
isect_memberEquality_alt, 
axiomEquality, 
isectIsTypeImplies, 
inhabitedIsType, 
because_Cache, 
functionExtensionality, 
dependent_functionElimination, 
Error :memTop, 
productElimination, 
independent_isectElimination, 
dependent_pairEquality_alt
Latex:
\mforall{}[C:SmallCategory].  \mforall{}[X:ps\_context\{j:l\}(C)].  \mforall{}[A:\{X  \mvdash{}  \_\}].  \mforall{}[B:\{X.A  \mvdash{}  \_\}].
    (SigmaElim  o  SigmaUnElim  =  1(X.A.B))
Date html generated:
2020_05_20-PM-01_32_45
Last ObjectModification:
2020_04_02-PM-06_45_38
Theory : presheaf!models!of!type!theory
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