Nuprl Lemma : quotient-of-quotient

T:Type. ∀R:T ⟶ T ⟶ ℙ.
  (EquivRel(T;x,y.x y)
   (∀Q:(x,y:T//(x y)) ⟶ (x,y:T//(x y)) ⟶ ℙ
        (EquivRel(x,y:T//(x y);u,v.u v)  u,v:x,y:T//(x y)//(u v) ≡ x,y:T//(x y))))


Proof




Definitions occuring in Statement :  equiv_rel: EquivRel(T;x,y.E[x; y]) quotient: x,y:A//B[x; y] ext-eq: A ≡ B prop: infix_ap: y all: x:A. B[x] implies:  Q function: x:A ⟶ B[x] universe: Type
Definitions unfolded in proof :  all: x:A. B[x] implies:  Q member: t ∈ T uall: [x:A]. B[x] so_lambda: λ2y.t[x; y] prop: subtype_rel: A ⊆B so_apply: x[s1;s2] uimplies: supposing a so_lambda: λ2x.t[x] so_apply: x[s] istype: istype(T) ext-eq: A ≡ B and: P ∧ Q quotient: x,y:A//B[x; y] infix_ap: y guard: {T}
Lemmas referenced :  equiv-on-quotient quotient_wf infix_ap_wf subtype_rel_dep_function subtype_quotient equal-wf-base quotient_subtype_quotient subtype_rel_self equiv_rel_wf quotient-member-eq
Rules used in proof :  sqequalSubstitution sqequalTransitivity computationStep sqequalReflexivity Error :lambdaFormation_alt,  cut introduction extract_by_obid sqequalHypSubstitution dependent_functionElimination thin hypothesisEquality independent_functionElimination hypothesis isectElimination because_Cache sqequalRule Error :lambdaEquality_alt,  instantiate cumulativity universeEquality applyEquality Error :inhabitedIsType,  independent_isectElimination functionEquality functionExtensionality Error :universeIsType,  independent_pairFormation pointwiseFunctionalityForEquality pertypeElimination productElimination equalityTransitivity equalitySymmetry Error :equalityIsType1,  productEquality Error :functionIsType,  hyp_replacement

Latex:
\mforall{}T:Type.  \mforall{}R:T  {}\mrightarrow{}  T  {}\mrightarrow{}  \mBbbP{}.
    (EquivRel(T;x,y.x  R  y)
    {}\mRightarrow{}  (\mforall{}Q:(x,y:T//(x  R  y))  {}\mrightarrow{}  (x,y:T//(x  R  y))  {}\mrightarrow{}  \mBbbP{}
                (EquivRel(x,y:T//(x  R  y);u,v.u  Q  v)  {}\mRightarrow{}  u,v:x,y:T//(x  R  y)//(u  Q  v)  \mequiv{}  x,y:T//(x  Q  y))))



Date html generated: 2019_06_20-PM-00_33_09
Last ObjectModification: 2018_09_30-PM-00_36_21

Theory : quot_1


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