Nuprl Lemma : presheaf-sigma-equal
∀[C:SmallCategory]. ∀[X:ps_context{j:l}(C)]. ∀[A:{X ⊢ _}]. ∀[B:{X.A ⊢ _}]. ∀[w,y:{X ⊢ _:Σ A B}].
  (w = y ∈ {X ⊢ _:Σ A B}) supposing ((w.2 = y.2 ∈ {X ⊢ _:(B)[w.1]}) and (w.1 = y.1 ∈ {X ⊢ _:A}))
Proof
Definitions occuring in Statement : 
presheaf-snd: p.2
, 
presheaf-fst: p.1
, 
presheaf-sigma: Σ A B
, 
pscm-id-adjoin: [u]
, 
psc-adjoin: X.A
, 
presheaf-term: {X ⊢ _:A}
, 
pscm-ap-type: (AF)s
, 
presheaf-type: {X ⊢ _}
, 
ps_context: __⊢
, 
uimplies: b supposing a
, 
uall: ∀[x:A]. B[x]
, 
equal: s = t ∈ T
, 
small-category: SmallCategory
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
uimplies: b supposing a
, 
squash: ↓T
, 
subtype_rel: A ⊆r B
, 
true: True
, 
and: P ∧ Q
Lemmas referenced : 
presheaf-pair-eta, 
presheaf-pair_wf, 
presheaf-term_wf, 
pscm-ap-type_wf, 
psc-adjoin_wf, 
ps_context_cumulativity2, 
presheaf-type-cumulativity2, 
pscm-id-adjoin_wf, 
small-category-cumulativity-2, 
presheaf-fst_wf, 
presheaf-snd_wf, 
subtype_rel-equal, 
presheaf-sigma_wf, 
presheaf-type_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation_alt, 
introduction, 
cut, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
hypothesisEquality, 
because_Cache, 
applyEquality, 
lambdaEquality_alt, 
imageElimination, 
equalityTransitivity, 
hypothesis, 
equalitySymmetry, 
universeIsType, 
instantiate, 
sqequalRule, 
natural_numberEquality, 
imageMemberEquality, 
baseClosed, 
equalityIstype, 
independent_isectElimination, 
dependent_set_memberEquality_alt, 
independent_pairFormation, 
productIsType, 
inhabitedIsType, 
applyLambdaEquality, 
setElimination, 
rename, 
productElimination, 
isect_memberEquality_alt, 
axiomEquality, 
isectIsTypeImplies
Latex:
\mforall{}[C:SmallCategory].  \mforall{}[X:ps\_context\{j:l\}(C)].  \mforall{}[A:\{X  \mvdash{}  \_\}].  \mforall{}[B:\{X.A  \mvdash{}  \_\}].  \mforall{}[w,y:\{X  \mvdash{}  \_:\mSigma{}  A  B\}].
    (w  =  y)  supposing  ((w.2  =  y.2)  and  (w.1  =  y.1))
Date html generated:
2020_05_20-PM-01_33_37
Last ObjectModification:
2020_04_03-AM-01_04_48
Theory : presheaf!models!of!type!theory
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