Nuprl Lemma : rnonzero_functionality

∀x,y:ℝ.  ((x = y) ⇒ (rnonzero(x) ⇐⇒ rnonzero(y)))


Proof




Definitions occuring in Statement :  rnonzero: rnonzero(x),  req: x = y,  real: ℝ,  all: ∀x:A. B[x],  iff: P ⇐⇒ Q,  implies: P ⇒ Q
Definitions unfolded in proof :  all: ∀x:A. B[x],  implies: P ⇒ Q,  member: t ∈ T,  prop: ℙ,  uall: ∀[x:A]. B[x],  real: ℝ,  rnonzero: rnonzero(x),  exists: ∃x:A. B[x],  uimplies: b supposing a,  nat_plus: ℕ+,  subtype_rel: A ⊆r B,  nat: ℕ,  decidable: Dec(P),  or: P ∨ Q,  less_than: a < b,  squash: ↓T,  and: P ∧ Q,  satisfiable_int_formula: satisfiable_int_formula(fmla),  false: False,  not: ¬A,  top: Top,  less_than': less_than'(a;b),  true: True,  req: x = y,  le: A ≤ B,  uiff: uiff(P;Q),  rev_uimplies: rev_uimplies(P;Q),  ge: i ≥ j ,  guard: {T},  iff: P ⇐⇒ Q,  rev_implies: P ⇐ Q
Lemmas referenced :  rnonzero_wf,  req_wf,  real_wf,  rnonzero-lemma1,  nat_plus_properties,  decidable__le,  absval_wf,  less_than_wf,  nat_wf,  satisfiable-full-omega-tt,  intformand_wf,  intformnot_wf,  intformle_wf,  itermConstant_wf,  itermVar_wf,  intformless_wf,  int_formula_prop_and_lemma,  int_formula_prop_not_lemma,  int_formula_prop_le_lemma,  int_term_value_constant_lemma,  int_term_value_var_lemma,  int_formula_prop_less_lemma,  int_formula_prop_wf,  mul_nat_plus,  itermMultiply_wf,  int_term_value_mul_lemma,  subtract_wf,  multiply-is-int-iff,  false_wf,  decidable__equal_int,  intformeq_wf,  itermAdd_wf,  itermSubtract_wf,  int_formula_prop_eq_lemma,  int_term_value_add_lemma,  int_term_value_subtract_lemma,  and_wf,  equal_wf,  le_wf,  le_functionality,  le_weakening,  int-triangle-inequality,  mul_cancel_in_le,  decidable__lt,  add-is-int-iff,  req_inversion
Rules used in proof :  cut,  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  lambdaFormation,  introduction,  extract_by_obid,  sqequalHypSubstitution,  isectElimination,  thin,  setElimination,  rename,  hypothesisEquality,  hypothesis,  productElimination,  independent_isectElimination,  dependent_functionElimination,  natural_numberEquality,  applyEquality,  dependent_set_memberEquality,  lambdaEquality,  sqequalRule,  unionElimination,  imageElimination,  dependent_pairFormation,  int_eqEquality,  intEquality,  isect_memberEquality,  voidElimination,  voidEquality,  independent_pairFormation,  computeAll,  imageMemberEquality,  baseClosed,  because_Cache,  independent_functionElimination,  multiplyEquality,  addEquality,  pointwiseFunctionality,  equalityTransitivity,  equalitySymmetry,  promote_hyp,  baseApply,  closedConclusion,  setEquality,  hyp_replacement,  Error :applyLambdaEquality

Latex:
\mforall{}x,y:\mBbbR{}.    ((x  =  y)  {}\mRightarrow{}  (rnonzero(x)  \mLeftarrow{}{}\mRightarrow{}  rnonzero(y)))



Date html generated: 2016_10_26-AM-09_04_12
Last ObjectModification: 2016_07_12-AM-08_14_38

Theory : reals


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