Nuprl Lemma : presheaf-it-unique
∀[C:SmallCategory]. ∀[X:ps_context{j:l}(C)]. ∀[t:{X ⊢ _:1}].  (t = * ∈ {X ⊢ _:1})
Proof
Definitions occuring in Statement : 
presheaf-it: *
, 
presheaf-unit: 1
, 
presheaf-term: {X ⊢ _:A}
, 
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
, 
presheaf-unit: 1
, 
discrete-presheaf-type: discr(T)
, 
all: ∀x:A. B[x]
, 
presheaf-term-at: u(a)
, 
subtype_rel: A ⊆r B
, 
presheaf-type-at: A(a)
, 
pi1: fst(t)
, 
unit: Unit
, 
uimplies: b supposing a
Lemmas referenced : 
presheaf_type_at_pair_lemma, 
equal-unit, 
presheaf-term-at_wf, 
presheaf-unit_wf, 
subtype_rel_self, 
unit_wf2, 
presheaf-it_wf, 
small-category-cumulativity-2, 
ps_context_cumulativity2, 
I_set_wf, 
cat-ob_wf, 
presheaf-term-equal, 
presheaf-term_wf, 
ps_context_wf, 
small-category_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation_alt, 
introduction, 
cut, 
functionExtensionality, 
sqequalRule, 
extract_by_obid, 
sqequalHypSubstitution, 
dependent_functionElimination, 
thin, 
Error :memTop, 
hypothesis, 
isectElimination, 
hypothesisEquality, 
applyEquality, 
instantiate, 
equalityTransitivity, 
equalitySymmetry, 
independent_isectElimination, 
universeIsType, 
isect_memberEquality_alt, 
axiomEquality, 
isectIsTypeImplies, 
inhabitedIsType
Latex:
\mforall{}[C:SmallCategory].  \mforall{}[X:ps\_context\{j:l\}(C)].  \mforall{}[t:\{X  \mvdash{}  \_:1\}].    (t  =  *)
Date html generated:
2020_05_20-PM-01_34_48
Last ObjectModification:
2020_04_02-PM-06_34_13
Theory : presheaf!models!of!type!theory
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