Nuprl Lemma : presheaf-sigma_wf

∀[C:SmallCategory]. ∀[X:ps_context{j:l}(C)]. ∀[A:{X ⊢ _}]. ∀[B:{X.A ⊢ _}].  (Σ A B ∈ X ⊢ )


Proof




Definitions occuring in Statement :  presheaf-sigma: Σ A B,  psc-adjoin: X.A,  presheaf-type: {X ⊢ _},  ps_context: __⊢,  uall: ∀[x:A]. B[x],  member: t ∈ T,  small-category: SmallCategory
Definitions unfolded in proof :  uall: ∀[x:A]. B[x],  member: t ∈ T,  presheaf-sigma: Σ A B,  presheaf-type: {X ⊢ _},  subtype_rel: A ⊆r B,  all: ∀x:A. B[x],  so_lambda: λ2x.t[x],  so_apply: x[s],  psc-restriction: f(s),  pi2: snd(t),  psc-adjoin: X.A,  psc-adjoin-set: (v;u),  pi1: fst(t),  and: P ∧ Q,  cand: A c∧ B,  squash: ↓T,  prop: ℙ,  true: True,  uimplies: b supposing a,  guard: {T},  iff: P ⇐⇒ Q,  rev_implies: P ⇐ Q,  implies: P ⇒ Q
Lemmas referenced :  presheaf-type-at_wf,  psc-adjoin_wf,  ps_context_cumulativity2,  presheaf-type-cumulativity2,  psc-adjoin-set_wf,  I_set_wf,  cat-ob_wf,  presheaf-type-ap-morph_wf,  pi1_wf_top,  pi2_wf,  subtype_rel_self,  small-category-cumulativity-2,  psc-restriction_wf,  cat-arrow_wf,  equal_wf,  squash_wf,  true_wf,  istype-universe,  cat-comp_wf,  presheaf-type-ap-morph-comp,  iff_weakening_equal,  presheaf-type-ap-morph-comp-eq,  psc-adjoin-set-restriction,  cat-id_wf,  subtype_rel-equal,  psc-restriction-id,  psc-restriction-comp,  presheaf-type_wf,  ps_context_wf,  small-category_wf,  presheaf-type-ap-morph-id
Rules used in proof :  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  isect_memberFormation_alt,  introduction,  cut,  dependent_set_memberEquality_alt,  dependent_pairEquality_alt,  lambdaEquality_alt,  productEquality,  extract_by_obid,  sqequalHypSubstitution,  isectElimination,  thin,  hypothesisEquality,  hypothesis,  instantiate,  applyEquality,  because_Cache,  sqequalRule,  dependent_functionElimination,  universeIsType,  productElimination,  independent_pairEquality,  Error :memTop,  productIsType,  inhabitedIsType,  functionIsType,  lambdaFormation_alt,  independent_pairFormation,  imageElimination,  equalityTransitivity,  equalitySymmetry,  universeEquality,  natural_numberEquality,  imageMemberEquality,  baseClosed,  independent_isectElimination,  independent_functionElimination,  equalityIstype,  axiomEquality,  isect_memberEquality_alt,  isectIsTypeImplies

Latex:
\mforall{}[C:SmallCategory].  \mforall{}[X:ps\_context\{j:l\}(C)].  \mforall{}[A:\{X  \mvdash{}  \_\}].  \mforall{}[B:\{X.A  \mvdash{}  \_\}].    (\mSigma{}  A  B  \mmember{}  X  \mvdash{}  )



Date html generated: 2020_05_20-PM-01_31_23
Last ObjectModification: 2020_04_02-PM-03_03_10

Theory : presheaf!models!of!type!theory


Home Index