Nuprl Lemma : discrete-sigma-equiv

∀A:Type. ∀B:A ⟶ Type. ∀X:j⊢.  {X ⊢ _:Equiv(Σ discr(A) discrete-family(A;a.B[a]);discr(a:A × B[a]))}


Proof




Definitions occuring in Statement :  discrete-family: discrete-family(A;a.B[a]),  cubical-equiv: Equiv(T;A),  discrete-cubical-type: discr(T),  cubical-sigma: Σ A B,  cubical-term: {X ⊢ _:A},  cubical_set: CubicalSet,  so_apply: x[s],  all: ∀x:A. B[x],  function: x:A ⟶ B[x],  product: x:A × B[x],  universe: Type
Definitions unfolded in proof :  all: ∀x:A. B[x],  member: t ∈ T,  uall: ∀[x:A]. B[x],  so_lambda: λ2x.t[x],  so_apply: x[s],  discrete-family: discrete-family(A;a.B[a]),  cc-snd: q,  cc-fst: p,  csm-comp: G o F,  csm-adjoin: (s;u),  csm-ap-type: (AF)s,  compose: f o g,  csm-ap: (s)x,  pi2: snd(t),  subtype_rel: A ⊆r B,  uimplies: b supposing a,  squash: ↓T,  prop: ℙ,  true: True,  discrete-cubical-type: discr(T),  cubical-lam: cubical-lam(X;b),  cubical-app: app(w; u),  cubical-lambda: (λb),  cube-context-adjoin: X.A,  discrete-pair-inv: discrete-pair-inv(X;b),  discrete-pair: discrete-pair(p),  cubical-pair: cubical-pair(u;v),  cubical-snd: p.2,  cubical-fst: p.1,  cubical-term-at: u(a),  cc-adjoin-cube: (v;u),  csm-ap-term: (t)s,  pi1: fst(t),  implies: P ⇒ Q,  and: P ∧ Q,  iff: P ⇐⇒ Q,  rev_implies: P ⇐ Q,  fiber-member: fiber-member(p),  fiber-point: fiber-point(t;c)
Lemmas referenced :  cubical_set_wf,  istype-universe,  cubical-sigma-p,  cubical-sigma_wf,  discrete-cubical-type_wf,  discrete-family_wf,  csm-discrete-cubical-type,  discrete-pair_wf,  cube-context-adjoin_wf,  cubical_set_cumulativity-i-j,  cubical-type-cumulativity2,  cc-snd_wf,  csm-discrete-family,  cubical-term-eqcd,  discrete-pair-inv_wf,  csm-discrete-sigma,  cc-fst_wf,  path-type_wf,  squash_wf,  true_wf,  istype-cubical-term,  cubical-type_wf,  csm-ap-type_wf,  cubical-refl_wf,  I_cube_wf,  fset_wf,  nat_wf,  cubical-term-equal,  cubical_type_at_pair_lemma,  I_cube_pair_redex_lemma,  cubical-fiber_wf,  csm-ap-term_wf,  cubical-fun_wf,  cubical-lam_wf,  csm-cubical-fun,  csm-cubical-fiber,  equal-fiber-discrete,  fiber-point_wf,  csm-fiber-point,  fiber-discrete-equal,  fiber-member_wf,  equal_wf,  discrete-pair-injection,  cubical-term_wf,  cubical-term-at_wf,  discrete-pair-inv-property,  cubical-fst-pair,  equiv-witness_wf,  cubical-lambda_wf,  contractible-type_wf,  contr-witness_wf
Rules used in proof :  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  lambdaFormation_alt,  cut,  universeIsType,  thin,  instantiate,  introduction,  extract_by_obid,  hypothesis,  functionIsType,  hypothesisEquality,  inhabitedIsType,  sqequalHypSubstitution,  isectElimination,  universeEquality,  dependent_functionElimination,  sqequalRule,  lambdaEquality_alt,  applyEquality,  Error :memTop,  because_Cache,  equalityTransitivity,  equalitySymmetry,  independent_isectElimination,  hyp_replacement,  cumulativity,  productEquality,  imageElimination,  natural_numberEquality,  imageMemberEquality,  baseClosed,  functionExtensionality,  productElimination,  dependent_pairEquality_alt,  equalityIstype,  independent_functionElimination,  dependent_set_memberEquality_alt,  independent_pairFormation,  productIsType,  applyLambdaEquality,  setElimination,  rename

Latex:
\mforall{}A:Type.  \mforall{}B:A  {}\mrightarrow{}  Type.  \mforall{}X:j\mvdash{}.    \{X  \mvdash{}  \_:Equiv(\mSigma{}  discr(A)  discrete-family(A;a.B[a]);discr(a:A  \mtimes{}  B[a]))\}



Date html generated: 2020_05_20-PM-03_41_58
Last ObjectModification: 2020_04_20-PM-06_17_22

Theory : cubical!type!theory


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