Nuprl Lemma : extensional-discrete-real-fun-is-constant

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


Proof




Definitions occuring in Statement :  rccint: [l, u],  i-member: r ∈ I,  req: x = y,  real: ℝ,  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],  int: ℤ,  equal: s = t ∈ T
Definitions unfolded in proof :  all: ∀x:A. B[x],  member: t ∈ T,  uimplies: b supposing a,  top: Top,  and: P ∧ Q,  uall: ∀[x:A]. B[x],  guard: {T},  rfun: I ⟶ℝ,  prop: ℙ,  iff: P ⇐⇒ Q,  implies: P ⇒ Q,  real-fun: real-fun(f;a;b),  uiff: uiff(P;Q),  so_lambda: λ2x.t[x],  so_apply: x[s],  real-cont: real-cont(f;a;b),  nat_plus: ℕ+,  less_than: a < b,  squash: ↓T,  less_than': less_than'(a;b),  true: True,  exists: ∃x:A. B[x],  decidable: Dec(P),  or: P ∨ Q,  false: False,  not: ¬A,  satisfiable_int_formula: satisfiable_int_formula(fmla),  rneq: x ≠ y,  rev_implies: P ⇐ Q,  le: A ≤ B,  rleq: x ≤ y,  rnonneg: rnonneg(x),  subtype_rel: A ⊆r B,  nat: ℕ,  rdiv: (x/y),  req_int_terms: t1 ≡ t2,  int_seg: {i..j-},  lelt: i ≤ j < k,  ge: i ≥ j ,  rless: x < y,  sq_exists: ∃x:{A| B[x]},  sq_type: SQType(T),  real: ℝ,  sq_stable: SqStable(P),  rbetween: x≤y≤z,  rev_uimplies: rev_uimplies(P;Q),  i-member: r ∈ I,  rccint: [l, u],  label: ...$L... t,  full-partition: full-partition(I;p),  partition: partition(I)
Lemmas referenced :  real-fun-iff-continuous,  member_rccint_lemma,  rleq_transitivity,  int-to-real_wf,  real_wf,  rleq_wf,  i-member_wf,  rccint_wf,  req-int,  req_wf,  set_wf,  all_wf,  equal_wf,  less_than_wf,  rabs_wf,  rsub_wf,  decidable__equal_int,  subtract-is-int-iff,  full-omega-unsat,  intformand_wf,  intformnot_wf,  intformeq_wf,  itermVar_wf,  itermSubtract_wf,  itermConstant_wf,  int_formula_prop_and_lemma,  int_formula_prop_not_lemma,  int_formula_prop_eq_lemma,  int_term_value_var_lemma,  int_term_value_subtract_lemma,  int_term_value_constant_lemma,  int_formula_prop_wf,  false_wf,  subtract_wf,  rdiv_wf,  rless-int,  rless_wf,  rleq_functionality,  rabs_functionality,  rsub-int,  req_weakening,  rmul_preserves_rleq2,  rleq-int,  less_than'_wf,  rmul_wf,  nat_plus_wf,  absval_wf,  nat_wf,  itermMultiply_wf,  rinv_wf2,  req_transitivity,  squash_wf,  true_wf,  rabs-int,  rmul-int,  rmul-rinv,  req-iff-rsub-is-0,  real_polynomial_null,  real_term_value_sub_lemma,  real_term_value_mul_lemma,  real_term_value_var_lemma,  real_term_value_const_lemma,  absval_unfold,  decidable__lt,  top_wf,  intformless_wf,  intformle_wf,  int_formula_prop_less_lemma,  int_formula_prop_le_lemma,  int_term_value_mul_lemma,  itermMinus_wf,  int_term_value_minus_lemma,  partition-exists,  rccint-icompact,  list_set_type,  full-partition_wf,  full-partition-point-member,  mesh-property,  int_seg_properties,  length_wf,  int_seg_wf,  le_wf,  nat_properties,  ge_wf,  decidable__le,  select_wf,  nat_plus_properties,  subtype_base_sq,  int_subtype_base,  sq_stable__less_than,  adjacent-full-partition-points,  lelt_wf,  subtract-add-cancel,  rbetween_wf,  partition-mesh_wf,  rabs-of-nonneg,  sq_stable__rleq,  iff_weakening_equal,  length_of_cons_lemma,  right_endpoint_rccint_lemma,  add_nat_plus,  length_wf_nat,  append_wf,  cons_wf,  nil_wf,  length-append,  length_of_nil_lemma,  add-is-int-iff,  itermAdd_wf,  int_term_value_add_lemma
Rules used in proof :  cut,  introduction,  extract_by_obid,  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  lambdaFormation,  hypothesis,  sqequalHypSubstitution,  dependent_functionElimination,  thin,  hypothesisEquality,  isect_memberFormation,  setElimination,  rename,  isect_memberEquality,  voidElimination,  voidEquality,  sqequalRule,  independent_isectElimination,  productElimination,  isectElimination,  lambdaEquality,  applyEquality,  functionExtensionality,  setEquality,  productEquality,  independent_functionElimination,  dependent_set_memberEquality,  axiomEquality,  because_Cache,  functionEquality,  intEquality,  natural_numberEquality,  independent_pairFormation,  imageMemberEquality,  baseClosed,  unionElimination,  pointwiseFunctionality,  equalityTransitivity,  equalitySymmetry,  promote_hyp,  baseApply,  closedConclusion,  approximateComputation,  dependent_pairFormation,  int_eqEquality,  inrFormation,  independent_pairEquality,  minusEquality,  multiplyEquality,  imageElimination,  lessCases,  sqequalAxiom,  intWeakElimination,  instantiate,  cumulativity,  addEquality,  universeEquality,  applyLambdaEquality

Latex:
\mforall{}a,b:\mBbbR{}.  \mforall{}f:\{x:\mBbbR{}|  x  \mmember{}  [a,  b]\}    {}\mrightarrow{}  \mBbbZ{}.
    \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: 2017_10_03-AM-09_59_57
Last ObjectModification: 2017_06_01-PM-04_32_03

Theory : reals


Home Index