Nuprl Lemma : real-subset-connected-lemma

∀X:ℝ ⟶ ℙ
  (dense-in-interval((-∞, ∞);X)
  ⇒ (∀a,b:{x:ℝ| X x}  ⟶ 𝔹.
        ((∃x:{x:ℝ| X x} . (↑(a x)))
        ⇒ (∃x:{x:ℝ| X x} . (↑(b x)))
        ⇒ (∀x:{x:ℝ| X x} . ((↑(a x)) ∨ (↑(b x))))
        ⇒ (∃f,g:ℕ ⟶ {x:ℝ| X x} 
             ∃x:ℝ. ((∀n:ℕ. (↑(a (f n)))) ∧ (∀n:ℕ. (↑(b (g n)))) ∧ lim n→∞.f n = x ∧ lim n→∞.g n = x)))))


Proof




Definitions occuring in Statement :  dense-in-interval: dense-in-interval(I;X),  riiint: (-∞, ∞),  converges-to: lim n→∞.x[n] = y,  real: ℝ,  nat: ℕ,  assert: ↑b,  bool: 𝔹,  prop: ℙ,  all: ∀x:A. B[x],  exists: ∃x:A. B[x],  implies: P ⇒ Q,  or: P ∨ Q,  and: P ∧ Q,  set: {x:A| B[x]} ,  apply: f a,  function: x:A ⟶ B[x]
Definitions unfolded in proof :  all: ∀x:A. B[x],  implies: P ⇒ Q,  member: t ∈ T,  prop: ℙ,  uall: ∀[x:A]. B[x],  subtype_rel: A ⊆r B,  so_lambda: λ2x.t[x],  so_apply: x[s],  uimplies: b supposing a,  top: Top,  dense-in-interval: dense-in-interval(I;X),  rneq: x ≠ y,  guard: {T},  or: P ∨ Q,  iff: P ⇐⇒ Q,  and: P ∧ Q,  rev_implies: P ⇐ Q,  less_than: a < b,  squash: ↓T,  less_than': less_than'(a;b),  true: True,  exists: ∃x:A. B[x],  cand: A c∧ B,  uiff: uiff(P;Q),  rev_uimplies: rev_uimplies(P;Q),  rless: x < y,  sq_exists: ∃x:A [B[x]],  nat_plus: ℕ+,  decidable: Dec(P),  not: ¬A,  satisfiable_int_formula: satisfiable_int_formula(fmla),  false: False,  sq_type: SQType(T),  int_nzero: ℤ-o,  nequal: a ≠ b ∈ T ,  rdiv: (x/y),  req_int_terms: t1 ≡ t2,  rge: x ≥ y,  rgt: x > y,  pi1: fst(t),  pi2: snd(t),  sq_stable: SqStable(P),  nat: ℕ,  le: A ≤ B,  real: ℝ,  ge: i ≥ j ,  bool: 𝔹,  unit: Unit,  it: ⋅,  btrue: tt,  ifthenelse: if b then t else f fi ,  bfalse: ff,  bnot: ¬bb,  assert: ↑b,  label: ...$L... t,  rbetween: x≤y≤z,  rleq: x ≤ y,  rnonneg: rnonneg(x),  int_upper: {i...}
Lemmas referenced :  dense-in-interval_wf,  riiint_wf,  subtype_rel_dep_function,  real_wf,  i-member_wf,  member_riiint_lemma,  subtype_rel_self,  set_wf,  rless_wf,  assert_wf,  all_wf,  or_wf,  bool_wf,  rdiv_wf,  radd_wf,  rmul_wf,  int-to-real_wf,  rless-int,  true_wf,  rmul_preserves_rless,  rmul_preserves_rleq,  rsub_wf,  rleq_wf,  rinv_wf2,  itermSubtract_wf,  itermMultiply_wf,  itermAdd_wf,  itermConstant_wf,  itermVar_wf,  subtype_base_sq,  int_subtype_base,  nat_plus_properties,  decidable__equal_int,  full-omega-unsat,  intformnot_wf,  intformeq_wf,  int_formula_prop_not_lemma,  int_formula_prop_eq_lemma,  int_term_value_constant_lemma,  int_term_value_mul_lemma,  int_formula_prop_wf,  equal-wf-base,  nequal_wf,  rless-implies-rless,  req-iff-rsub-is-0,  rless_functionality,  req_transitivity,  radd_functionality,  rmul-rinv3,  int-rinv-cancel,  real_polynomial_null,  real_term_value_sub_lemma,  real_term_value_mul_lemma,  real_term_value_add_lemma,  real_term_value_const_lemma,  real_term_value_var_lemma,  rleq_functionality,  rless_transitivity2,  rleq_weakening_rless,  rleq_functionality_wrt_implies,  radd_functionality_wrt_rless1,  rleq_weakening_equal,  rleq_weakening,  radd-preserves-rleq,  sq_stable__rless,  pi1_wf_top,  pi2_wf,  equal_wf,  exists_wf,  subtype_rel_product,  top_wf,  primrec_wf,  int_seg_wf,  nat_wf,  primrec0_lemma,  false_wf,  le_wf,  sq_stable__less_than,  nat_properties,  nat_plus_wf,  decidable__le,  intformand_wf,  intformle_wf,  int_formula_prop_and_lemma,  int_formula_prop_le_lemma,  int_term_value_add_lemma,  int_term_value_var_lemma,  sq_stable__assert,  add-subtract-cancel,  bool_subtype_base,  squash_wf,  eq_int_eq_false,  bfalse_wf,  iff_weakening_equal,  primrec-unroll,  lt_int_wf,  eqtt_to_assert,  assert_of_lt_int,  eqff_to_assert,  bool_cases_sqequal,  assert-bnot,  not_functionality_wrt_uiff,  less_than_wf,  intformless_wf,  int_formula_prop_less_lemma,  ifthenelse_wf,  equal_functionality_wrt_subtype_rel2,  rless_transitivity1,  real-regular,  and_wf,  regular-int-seq_wf,  rmul_preserves_rleq2,  rleq-int,  rless_functionality_wrt_implies,  common-limit-squeeze,  rnexp_wf,  rnexp-converges-ext,  rabs_wf,  rleq-int-fractions2,  rless-int-fractions3,  rabs-of-nonneg,  req_weakening,  rmul-limit,  constant-limit,  converges-to_functionality,  rmul_comm,  rmul-zero,  ge_wf,  less_than'_wf,  subtract_wf,  int_term_value_subtract_lemma,  exp0_lemma,  rsub_functionality_wrt_rleq,  rminus_wf,  itermMinus_wf,  rnexp_zero_lemma,  real_term_value_minus_lemma,  exp-nondecreasing,  subtract-add-cancel,  rbetween_wf,  rnexp_step,  rless-int-fractions2,  rleq-implies-rleq,  rmul_functionality,  converges-to_wf,  rless-cases,  rneq_wf
Rules used in proof :  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  lambdaFormation,  cut,  introduction,  extract_by_obid,  sqequalHypSubstitution,  isectElimination,  thin,  hypothesis,  hypothesisEquality,  applyEquality,  instantiate,  cumulativity,  sqequalRule,  lambdaEquality,  universeEquality,  setEquality,  independent_isectElimination,  dependent_functionElimination,  isect_memberEquality,  voidElimination,  voidEquality,  setElimination,  rename,  functionEquality,  because_Cache,  dependent_set_memberEquality,  natural_numberEquality,  inrFormation,  productElimination,  independent_functionElimination,  independent_pairFormation,  imageMemberEquality,  baseClosed,  dependent_pairFormation,  productEquality,  intEquality,  unionElimination,  approximateComputation,  equalityTransitivity,  equalitySymmetry,  minusEquality,  int_eqEquality,  imageElimination,  independent_pairEquality,  functionExtensionality,  inlFormation,  promote_hyp,  addEquality,  baseApply,  closedConclusion,  equalityElimination,  applyLambdaEquality,  multiplyEquality,  intWeakElimination,  axiomEquality,  hyp_replacement

Latex:
\mforall{}X:\mBbbR{}  {}\mrightarrow{}  \mBbbP{}
    (dense-in-interval((-\minfty{},  \minfty{});X)
    {}\mRightarrow{}  (\mforall{}a,b:\{x:\mBbbR{}|  X  x\}    {}\mrightarrow{}  \mBbbB{}.
                ((\mexists{}x:\{x:\mBbbR{}|  X  x\}  .  (\muparrow{}(a  x)))
                {}\mRightarrow{}  (\mexists{}x:\{x:\mBbbR{}|  X  x\}  .  (\muparrow{}(b  x)))
                {}\mRightarrow{}  (\mforall{}x:\{x:\mBbbR{}|  X  x\}  .  ((\muparrow{}(a  x))  \mvee{}  (\muparrow{}(b  x))))
                {}\mRightarrow{}  (\mexists{}f,g:\mBbbN{}  {}\mrightarrow{}  \{x:\mBbbR{}|  X  x\} 
                          \mexists{}x:\mBbbR{}
                            ((\mforall{}n:\mBbbN{}.  (\muparrow{}(a  (f  n))))  \mwedge{}  (\mforall{}n:\mBbbN{}.  (\muparrow{}(b  (g  n))))  \mwedge{}  lim  n\mrightarrow{}\minfty{}.f  n  =  x  \mwedge{}  lim  n\mrightarrow{}\minfty{}.g  n  =  x)))))



Date html generated: 2019_10_30-AM-07_21_21
Last ObjectModification: 2018_08_31-AM-10_00_27

Theory : reals


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