Nuprl Lemma : quo-lift_wf

∀A,B:Type. ∀f:A ⟶ B. ∀R:B ⟶ B ⟶ ℙ.  (EquivRel(B;x,y.x R y) ⇒ (quo-lift(f) ∈ (x,y:A//(x R_f y)) ⟶ (x,y:B//(x R y))))


Proof




Definitions occuring in Statement :  quo-lift: quo-lift(f),  preima_of_rel: R_f,  equiv_rel: EquivRel(T;x,y.E[x; y]),  quotient: x,y:A//B[x; y],  prop: ℙ,  infix_ap: x f y,  all: ∀x:A. B[x],  implies: P ⇒ Q,  member: t ∈ T,  function: x:A ⟶ B[x],  universe: Type
Definitions unfolded in proof :  all: ∀x:A. B[x],  implies: P ⇒ Q,  member: t ∈ T,  uall: ∀[x:A]. B[x],  so_lambda: λ2x y.t[x; y],  infix_ap: x f y,  so_apply: x[s1;s2],  uimplies: b supposing a,  quotient: x,y:A//B[x; y],  and: P ∧ Q,  prop: ℙ,  subtype_rel: A ⊆r B,  preima_of_rel: R_f,  quo-lift: quo-lift(f)
Lemmas referenced :  preima_of_equiv_rel,  quotient_wf,  equal-wf-base,  preima_of_rel_wf,  equiv_rel_wf,  quotient-member-eq
Rules used in proof :  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  lambdaFormation,  cut,  introduction,  extract_by_obid,  sqequalHypSubstitution,  dependent_functionElimination,  thin,  hypothesisEquality,  independent_functionElimination,  hypothesis,  functionExtensionality,  pointwiseFunctionalityForEquality,  isectElimination,  cumulativity,  sqequalRule,  lambdaEquality,  applyEquality,  independent_isectElimination,  pertypeElimination,  productElimination,  productEquality,  because_Cache,  universeEquality,  functionEquality

Latex:
\mforall{}A,B:Type.  \mforall{}f:A  {}\mrightarrow{}  B.  \mforall{}R:B  {}\mrightarrow{}  B  {}\mrightarrow{}  \mBbbP{}.
    (EquivRel(B;x,y.x  R  y)  {}\mRightarrow{}  (quo-lift(f)  \mmember{}  (x,y:A//(x  R\_f  y))  {}\mrightarrow{}  (x,y:B//(x  R  y))))



Date html generated: 2016_10_21-AM-09_44_13
Last ObjectModification: 2016_08_08-PM-09_15_45

Theory : quot_1


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