Nuprl Lemma : rnonzero-iff

∀x:ℝ. (rnonzero(x) ⇐⇒ x ≠ r0)


Proof




Definitions occuring in Statement :  rneq: x ≠ y,  rnonzero: rnonzero(x),  int-to-real: r(n),  real: ℝ,  all: ∀x:A. B[x],  iff: P ⇐⇒ Q,  natural_number: $n
Definitions unfolded in proof :  int-to-real: r(n),  rneq: x ≠ y,  rnonzero: rnonzero(x),  rless: x < y,  all: ∀x:A. B[x],  iff: P ⇐⇒ Q,  and: P ∧ Q,  implies: P ⇒ Q,  exists: ∃x:A. B[x],  member: t ∈ T,  prop: ℙ,  uall: ∀[x:A]. B[x],  so_lambda: λ2x.t[x],  real: ℝ,  subtype_rel: A ⊆r B,  nat: ℕ,  so_apply: x[s],  rev_implies: P ⇐ Q,  or: P ∨ Q,  sq_exists: ∃x:{A| B[x]},  bool: 𝔹,  unit: Unit,  it: ⋅,  btrue: tt,  uiff: uiff(P;Q),  uimplies: b supposing a,  less_than: a < b,  less_than': less_than'(a;b),  top: Top,  true: True,  squash: ↓T,  not: ¬A,  false: False,  nat_plus: ℕ+,  satisfiable_int_formula: satisfiable_int_formula(fmla),  bfalse: ff,  sq_type: SQType(T),  guard: {T},  bnot: ¬bb,  ifthenelse: if b then t else f fi ,  assert: ↑b,  decidable: Dec(P)
Lemmas referenced :  exists_wf,  nat_plus_wf,  less_than_wf,  absval_wf,  nat_wf,  absval_unfold,  lt_int_wf,  bool_wf,  eqtt_to_assert,  assert_of_lt_int,  top_wf,  nat_plus_properties,  satisfiable-full-omega-tt,  intformand_wf,  intformless_wf,  itermConstant_wf,  itermVar_wf,  itermAdd_wf,  itermMultiply_wf,  int_formula_prop_and_lemma,  int_formula_prop_less_lemma,  int_term_value_constant_lemma,  int_term_value_var_lemma,  int_term_value_add_lemma,  int_term_value_mul_lemma,  int_formula_prop_wf,  eqff_to_assert,  equal_wf,  bool_cases_sqequal,  subtype_base_sq,  bool_subtype_base,  assert-bnot,  decidable__lt,  add-is-int-iff,  intformnot_wf,  itermMinus_wf,  int_formula_prop_not_lemma,  int_term_value_minus_lemma,  false_wf,  or_wf,  sq_exists_wf,  real_wf,  absval_ifthenelse,  assert_wf,  bnot_wf,  not_wf,  bool_cases,  iff_transitivity,  iff_weakening_uiff,  assert_of_bnot,  minus-is-int-iff
Rules used in proof :  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  sqequalRule,  lambdaFormation,  independent_pairFormation,  sqequalHypSubstitution,  productElimination,  thin,  cut,  introduction,  extract_by_obid,  isectElimination,  hypothesis,  lambdaEquality,  natural_numberEquality,  applyEquality,  setElimination,  rename,  hypothesisEquality,  unionElimination,  dependent_pairFormation,  because_Cache,  minusEquality,  equalityElimination,  independent_isectElimination,  lessCases,  isect_memberFormation,  sqequalAxiom,  isect_memberEquality,  voidElimination,  voidEquality,  imageMemberEquality,  baseClosed,  imageElimination,  independent_functionElimination,  int_eqEquality,  intEquality,  dependent_functionElimination,  computeAll,  equalityTransitivity,  equalitySymmetry,  promote_hyp,  instantiate,  cumulativity,  dependent_set_memberEquality,  pointwiseFunctionality,  baseApply,  closedConclusion,  addEquality,  multiplyEquality,  impliesFunctionality,  inrFormation,  dependent_set_memberFormation,  inlFormation

Latex:
\mforall{}x:\mBbbR{}.  (rnonzero(x)  \mLeftarrow{}{}\mRightarrow{}  x  \mneq{}  r0)



Date html generated: 2017_10_03-AM-08_27_04
Last ObjectModification: 2017_07_28-AM-07_24_40

Theory : reals


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