Nuprl Lemma : IVT-locally-non-constant-open

∀a:ℝ. ∀b:{b:ℝ| a < b} . ∀f:[a, b] ⟶ℝ.
  (∀a',b':ℝ.  (((a < a') ∧ (a' < b') ∧ (b' < b)) ⇒ (∀c:ℝ. locally-non-constant(f;a';b';c))))
  ⇒ (∀c:ℝ. ((f(a) < c) ⇒ (c < f(b)) ⇒ (∃x:ℝ. ((x ∈ (a, b)) ∧ (f(x) = c))))) 
  supposing ∀x,y:{x:ℝ| x ∈ [a, b]} .  ((x = y) ⇒ (f[x] = f[y]))


Proof




Definitions occuring in Statement :  locally-non-constant: locally-non-constant(f;a;b;c),  r-ap: f(x),  rfun: I ⟶ℝ,  rooint: (l, u),  rccint: [l, u],  i-member: r ∈ I,  rless: x < y,  req: x = y,  real: ℝ,  uimplies: b supposing a,  so_apply: x[s],  all: ∀x:A. B[x],  exists: ∃x:A. B[x],  implies: P ⇒ Q,  and: P ∧ Q,  set: {x:A| B[x]} 
Definitions unfolded in proof :  all: ∀x:A. B[x],  subinterval: I ⊆ J ,  member: t ∈ T,  top: Top,  implies: P ⇒ Q,  and: P ∧ Q,  cand: A c∧ B,  uall: ∀[x:A]. B[x],  guard: {T},  uimplies: b supposing a,  prop: ℙ,  sq_stable: SqStable(P),  squash: ↓T,  so_apply: x[s],  rfun: I ⟶ℝ,  so_lambda: λ2x.t[x],  i-member: r ∈ I,  rccint: [l, u],  subtype_rel: A ⊆r B,  continuous: f[x] continuous for x ∈ I,  i-approx: i-approx(I;n),  nat_plus: ℕ+,  rless: x < y,  sq_exists: ∃x:A [B[x]],  decidable: Dec(P),  or: P ∨ Q,  not: ¬A,  satisfiable_int_formula: satisfiable_int_formula(fmla),  exists: ∃x:A. B[x],  false: False,  iff: P ⇐⇒ Q,  rneq: x ≠ y,  rev_implies: P ⇐ Q,  rleq: x ≤ y,  rnonneg: rnonneg(x),  le: A ≤ B,  uiff: uiff(P;Q),  req_int_terms: t1 ≡ t2,  rev_uimplies: rev_uimplies(P;Q),  less_than': less_than'(a;b),  rge: x ≥ y,  r-ap: f(x),  rdiv: (x/y)
Lemmas referenced :  member_rooint_lemma,  istype-void,  member_rccint_lemma,  rleq_weakening_rless,  rless_wf,  sq_stable__rless,  req_witness,  function-is-continuous,  r-ap_wf,  rccint_wf,  rleq_weakening_equal,  locally-non-constant_wf,  rfun_subtype_3,  i-member_wf,  req_wf,  rfun_wf,  real_wf,  nat_plus_properties,  decidable__lt,  full-omega-unsat,  intformnot_wf,  intformless_wf,  itermConstant_wf,  istype-int,  int_formula_prop_not_lemma,  int_formula_prop_less_lemma,  int_term_value_constant_lemma,  int_formula_prop_wf,  istype-less_than,  rccint-icompact,  icompact_wf,  small-reciprocal-real,  rless-implies-rless,  int-to-real_wf,  rsub_wf,  sq_stable__and,  all_wf,  rleq_wf,  rabs_wf,  rdiv_wf,  rless-int,  intformand_wf,  itermVar_wf,  int_formula_prop_and_lemma,  int_term_value_var_lemma,  sq_stable__all,  sq_stable__rleq,  le_witness_for_triv,  itermSubtract_wf,  req-iff-rsub-is-0,  real_polynomial_null,  real_term_value_sub_lemma,  real_term_value_var_lemma,  real_term_value_const_lemma,  ravg-between,  rmin_strict_ub,  radd_wf,  ravg_wf,  trivial-rless-radd,  rmin_strict_lb,  rmin_wf,  rabs-difference-bound-rleq,  radd-preserves-rleq,  rminus_wf,  itermAdd_wf,  itermMinus_wf,  rmin_ub,  rleq_functionality,  real_term_value_add_lemma,  rmin_lb,  real_term_value_minus_lemma,  rmul_wf,  itermMultiply_wf,  rmul-nonneg-case1,  rleq-int,  istype-false,  real_term_value_mul_lemma,  rleq_functionality_wrt_implies,  radd_functionality_wrt_rleq,  req_weakening,  rinv_wf2,  req_transitivity,  radd_functionality,  rinv-as-rdiv,  radd-preserves-rless,  rless_functionality_wrt_implies,  rless_functionality,  rmax_strict_lb,  trivial-rsub-rless,  rmax_strict_ub,  rmax_wf,  rless_transitivity2,  rleq-rmax,  rmax_lb,  trivial-rleq-radd,  nat_plus_wf,  IVT-locally-non-constant,  rless_transitivity1,  sq_stable__req,  sq_stable__i-member,  rleq_transitivity,  rleq_weakening,  req_inversion,  continuous-implies-functional
Rules used in proof :  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  lambdaFormation_alt,  cut,  sqequalRule,  introduction,  extract_by_obid,  sqequalHypSubstitution,  dependent_functionElimination,  thin,  isect_memberEquality_alt,  voidElimination,  hypothesis,  productElimination,  isectElimination,  hypothesisEquality,  independent_isectElimination,  independent_pairFormation,  setElimination,  rename,  because_Cache,  productIsType,  universeIsType,  independent_functionElimination,  imageMemberEquality,  baseClosed,  imageElimination,  isect_memberFormation_alt,  lambdaEquality_alt,  applyEquality,  functionIsTypeImplies,  inhabitedIsType,  promote_hyp,  functionIsType,  setIsType,  dependent_set_memberEquality_alt,  natural_numberEquality,  unionElimination,  approximateComputation,  dependent_pairFormation_alt,  functionEquality,  productEquality,  closedConclusion,  inrFormation_alt,  int_eqEquality,  equalityTransitivity,  equalitySymmetry,  inlFormation_alt

Latex:
\mforall{}a:\mBbbR{}.  \mforall{}b:\{b:\mBbbR{}|  a  <  b\}  .  \mforall{}f:[a,  b]  {}\mrightarrow{}\mBbbR{}.
    (\mforall{}a',b':\mBbbR{}.    (((a  <  a')  \mwedge{}  (a'  <  b')  \mwedge{}  (b'  <  b))  {}\mRightarrow{}  (\mforall{}c:\mBbbR{}.  locally-non-constant(f;a';b';c))))
    {}\mRightarrow{}  (\mforall{}c:\mBbbR{}.  ((f(a)  <  c)  {}\mRightarrow{}  (c  <  f(b))  {}\mRightarrow{}  (\mexists{}x:\mBbbR{}.  ((x  \mmember{}  (a,  b))  \mwedge{}  (f(x)  =  c))))) 
    supposing  \mforall{}x,y:\{x:\mBbbR{}|  x  \mmember{}  [a,  b]\}  .    ((x  =  y)  {}\mRightarrow{}  (f[x]  =  f[y]))



Date html generated: 2019_10_30-AM-09_09_15
Last ObjectModification: 2019_04_02-AM-11_58_05

Theory : reals


Home Index