Nuprl Lemma : not-discontinuous

∀[f:ℝ ⟶ ℝ]. ∀[x:ℝ]. (¬discontinuous(f;x)) supposing ∀x,y:ℝ.  ((x = y) ⇒ ((f x) = (f y)))


Proof




Definitions occuring in Statement :  discontinuous: discontinuous(f;x),  req: x = y,  real: ℝ,  uimplies: b supposing a,  uall: ∀[x:A]. B[x],  all: ∀x:A. B[x],  not: ¬A,  implies: P ⇒ Q,  apply: f a,  function: x:A ⟶ B[x]
Definitions unfolded in proof :  uall: ∀[x:A]. B[x],  member: t ∈ T,  uimplies: b supposing a,  not: ¬A,  implies: P ⇒ Q,  false: False,  prop: ℙ,  so_lambda: λ2x.t[x],  so_apply: x[s],  discontinuous: discontinuous(f;x),  exists: ∃x:A. B[x],  all: ∀x:A. B[x],  subtype_rel: A ⊆r B,  rfun: I ⟶ℝ,  top: Top,  and: P ∧ Q,  iff: P ⇐⇒ Q,  rev_implies: P ⇐ Q,  less_than: a < b,  squash: ↓T,  less_than': less_than'(a;b),  true: True,  rsub: x - y,  real-fun: real-fun(f;a;b),  guard: {T},  real-cont: real-cont(f;a;b),  cand: A c∧ B,  sq_stable: SqStable(P),  uiff: uiff(P;Q),  rev_uimplies: rev_uimplies(P;Q),  le: A ≤ B,  rge: x ≥ y,  rgt: x > y,  nat_plus: ℕ+,  rneq: x ≠ y,  or: P ∨ Q,  rless: x < y,  sq_exists: ∃x:{A| B[x]},  decidable: Dec(P),  satisfiable_int_formula: satisfiable_int_formula(fmla)
Lemmas referenced :  discontinuous_wf,  real_wf,  all_wf,  req_wf,  real-fun-iff-continuous,  rsub_wf,  int-to-real_wf,  radd_wf,  member_rccint_lemma,  subtype_rel_dep_function,  rleq_wf,  subtype_rel_self,  set_wf,  radd-preserves-rless,  rless-int,  rminus_wf,  rless_wf,  rless_functionality,  req_weakening,  radd-int,  radd_functionality,  radd-zero-both,  req_transitivity,  radd-rminus-both,  radd-rminus-assoc,  radd-ac,  radd_comm,  req_inversion,  radd-assoc,  i-member_wf,  rccint_wf,  small-reciprocal-real,  rmin_wf,  rmin_strict_ub,  sq_stable__rless,  radd-preserves-rleq,  rmul_wf,  rleq-int,  false_wf,  uiff_transitivity,  rleq_functionality,  rminus-as-rmul,  rmul-identity1,  rmul-distrib2,  rmul_functionality,  uiff_transitivity2,  rmul-zero-both,  squash_wf,  true_wf,  rminus-int,  rabs-difference-bound-iff,  rleq_functionality_wrt_implies,  rleq_weakening_equal,  rleq_weakening_rless,  rmin-rleq,  radd_functionality_wrt_rless2,  rabs_wf,  rdiv_wf,  nat_plus_properties,  decidable__lt,  satisfiable-full-omega-tt,  intformand_wf,  intformnot_wf,  intformless_wf,  itermConstant_wf,  itermVar_wf,  int_formula_prop_and_lemma,  int_formula_prop_not_lemma,  int_formula_prop_less_lemma,  int_term_value_constant_lemma,  int_term_value_var_lemma,  int_formula_prop_wf,  rless_transitivity2,  rless_transitivity1,  rless_irreflexivity
Rules used in proof :  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  isect_memberFormation,  introduction,  cut,  lambdaFormation,  thin,  because_Cache,  hypothesis,  sqequalHypSubstitution,  independent_functionElimination,  voidElimination,  extract_by_obid,  isectElimination,  functionExtensionality,  applyEquality,  hypothesisEquality,  sqequalRule,  lambdaEquality,  dependent_functionElimination,  isect_memberEquality,  functionEquality,  equalityTransitivity,  equalitySymmetry,  productElimination,  natural_numberEquality,  independent_isectElimination,  voidEquality,  setEquality,  productEquality,  setElimination,  rename,  independent_pairFormation,  imageMemberEquality,  baseClosed,  addEquality,  addLevel,  levelHypothesis,  dependent_set_memberEquality,  imageElimination,  minusEquality,  promote_hyp,  inrFormation,  unionElimination,  dependent_pairFormation,  int_eqEquality,  intEquality,  computeAll

Latex:
\mforall{}[f:\mBbbR{}  {}\mrightarrow{}  \mBbbR{}].  \mforall{}[x:\mBbbR{}].  (\mneg{}discontinuous(f;x))  supposing  \mforall{}x,y:\mBbbR{}.    ((x  =  y)  {}\mRightarrow{}  ((f  x)  =  (f  y)))



Date html generated: 2016_10_26-AM-09_51_59
Last ObjectModification: 2016_08_12-PM-07_25_27

Theory : reals


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