Nuprl Lemma : sub_ps_context_functionality

[C:SmallCategory]. ∀[Y,X:ps_context{j:l}(C)]. ∀[A:{X ⊢ _}].
  sub_ps_context{[i j]:l}(C; Y.A; X.A) supposing sub_ps_context{j:l}(C; Y; X)


Proof




Definitions occuring in Statement :  psc-adjoin: X.A presheaf-type: {X ⊢ _} sub_ps_context: Y ⊆ X ps_context: __⊢ uimplies: supposing a uall: [x:A]. B[x] small-category: SmallCategory
Definitions unfolded in proof :  uall: [x:A]. B[x] member: t ∈ T uimplies: supposing a subtype_rel: A ⊆B psc-adjoin: X.A all: x:A. B[x] so_lambda: λ2x.t[x] so_apply: x[s] istype: istype(T) squash: T prop: true: True guard: {T} iff: ⇐⇒ Q and: P ∧ Q rev_implies:  Q implies:  Q sub_ps_context: Y ⊆ X
Lemmas referenced :  implies-sub_ps_context psc-adjoin_wf small-category-cumulativity-2 ps_context_cumulativity2 presheaf-type-cumulativity2 I_set_pair_redex_lemma subtype_rel_product I_set_wf presheaf-type-at_wf subset-presheaf-type subset-I_set cat-ob_wf psc_restriction_pair_lemma equal_wf squash_wf true_wf istype-universe ps-subset-restriction pi1_wf_top psc-restriction_wf subtype_rel_self iff_weakening_equal presheaf-type-ap-morph_wf pi2_wf cat-arrow_wf sub_ps_context_wf presheaf-type_wf ps_context_wf small-category_wf
Rules used in proof :  sqequalSubstitution sqequalTransitivity computationStep sqequalReflexivity isect_memberFormation_alt introduction cut thin instantiate extract_by_obid sqequalHypSubstitution isectElimination hypothesisEquality applyEquality hypothesis sqequalRule because_Cache independent_isectElimination dependent_functionElimination Error :memTop,  lambdaFormation_alt cumulativity lambdaEquality_alt universeIsType dependent_pairEquality_alt imageElimination equalityTransitivity equalitySymmetry universeEquality productElimination independent_pairEquality natural_numberEquality imageMemberEquality baseClosed independent_functionElimination productIsType axiomEquality isect_memberEquality_alt isectIsTypeImplies inhabitedIsType

Latex:
\mforall{}[C:SmallCategory].  \mforall{}[Y,X:ps\_context\{j:l\}(C)].  \mforall{}[A:\{X  \mvdash{}  \_\}].
    sub\_ps\_context\{[i  |  j]:l\}(C;  Y.A;  X.A)  supposing  sub\_ps\_context\{j:l\}(C;  Y;  X)



Date html generated: 2020_05_20-PM-01_35_27
Last ObjectModification: 2020_04_03-AM-01_23_09

Theory : presheaf!models!of!type!theory


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