Nuprl Lemma : extensional-interval-to-bool-constant

∀a:ℝ. ∀b:{b:ℝ| a ≤ b} . ∀f:{x:ℝ| x ∈ [a, b]}  ⟶ 𝔹.
  ∀x,y:{x:ℝ| x ∈ [a, b]} .  f x = f y supposing ∀x,y:{x:ℝ| x ∈ [a, b]} .  ((x = y) ⇒ f x = f y)


Proof




Definitions occuring in Statement :  rccint: [l, u],  i-member: r ∈ I,  rleq: x ≤ y,  req: x = y,  real: ℝ,  bool: 𝔹,  uimplies: b supposing a,  all: ∀x:A. B[x],  implies: P ⇒ Q,  set: {x:A| B[x]} ,  apply: f a,  function: x:A ⟶ B[x],  equal: s = t ∈ T
Definitions unfolded in proof :  all: ∀x:A. B[x],  uimplies: b supposing a,  member: t ∈ T,  uall: ∀[x:A]. B[x],  and: P ∧ Q,  cand: A c∧ B,  uiff: uiff(P;Q),  sq_stable: SqStable(P),  implies: P ⇒ Q,  squash: ↓T,  prop: ℙ,  subtype_rel: A ⊆r B,  i-member: r ∈ I,  rccint: [l, u],  rev_uimplies: rev_uimplies(P;Q),  top: Top,  iff: P ⇐⇒ Q,  guard: {T}
Lemmas referenced :  rmax_wf,  rmin_wf,  rleq-rmax,  rmax_lb,  sq_stable__rleq,  rmin-rleq,  rleq_wf,  extensional-real-to-bool-constant,  subtype_rel_self,  real_wf,  i-member_wf,  rccint_wf,  req_functionality,  rmax_functionality,  rmin_functionality,  req_weakening,  req_wf,  bool_wf,  member_rccint_lemma,  istype-void,  rmin_ub,  rmax-req,  rmin-req
Rules used in proof :  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  lambdaFormation_alt,  isect_memberFormation_alt,  introduction,  cut,  dependent_set_memberEquality_alt,  extract_by_obid,  sqequalHypSubstitution,  isectElimination,  thin,  hypothesisEquality,  setElimination,  rename,  hypothesis,  productElimination,  independent_pairFormation,  because_Cache,  independent_isectElimination,  independent_functionElimination,  sqequalRule,  imageMemberEquality,  baseClosed,  imageElimination,  productIsType,  universeIsType,  dependent_functionElimination,  lambdaEquality_alt,  applyEquality,  setEquality,  inhabitedIsType,  setIsType,  axiomEquality,  functionIsTypeImplies,  functionIsType,  equalityIstype,  isect_memberEquality_alt,  voidElimination,  equalityTransitivity,  equalitySymmetry

Latex:
\mforall{}a:\mBbbR{}.  \mforall{}b:\{b:\mBbbR{}|  a  \mleq{}  b\}  .  \mforall{}f:\{x:\mBbbR{}|  x  \mmember{}  [a,  b]\}    {}\mrightarrow{}  \mBbbB{}.
    \mforall{}x,y:\{x:\mBbbR{}|  x  \mmember{}  [a,  b]\}  .    f  x  =  f  y  supposing  \mforall{}x,y:\{x:\mBbbR{}|  x  \mmember{}  [a,  b]\}  .    ((x  =  y)  {}\mRightarrow{}  f  x  =  f  y)



Date html generated: 2019_10_30-AM-07_17_36
Last ObjectModification: 2019_04_10-PM-03_55_34

Theory : reals


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