Nuprl Lemma : rmax-positive

∀x,y:ℝ.  ((rpositive(x) ∨ rpositive(y)) ⇒ rpositive(rmax(x;y)))


Proof




Definitions occuring in Statement :  rpositive: rpositive(x),  rmax: rmax(x;y),  real: ℝ,  all: ∀x:A. B[x],  implies: P ⇒ Q,  or: P ∨ Q
Definitions unfolded in proof :  all: ∀x:A. B[x],  implies: P ⇒ Q,  or: P ∨ Q,  rpositive2: rpositive2(x),  exists: ∃x:A. B[x],  member: t ∈ T,  rmax: rmax(x;y),  squash: ↓T,  uall: ∀[x:A]. B[x],  prop: ℙ,  nat_plus: ℕ+,  real: ℝ,  true: True,  subtype_rel: A ⊆r B,  uimplies: b supposing a,  guard: {T},  iff: P ⇐⇒ Q,  and: P ∧ Q,  rev_implies: P ⇐ Q,  bool: 𝔹,  unit: Unit,  it: ⋅,  btrue: tt,  uiff: uiff(P;Q),  ifthenelse: if b then t else f fi ,  bfalse: ff,  sq_type: SQType(T),  bnot: ¬bb,  assert: ↑b,  false: False,  not: ¬A,  so_lambda: λ2x.t[x],  so_apply: x[s],  le: A ≤ B,  decidable: Dec(P),  satisfiable_int_formula: satisfiable_int_formula(fmla),  top: Top
Lemmas referenced :  le_wf,  squash_wf,  true_wf,  imax_unfold,  iff_weakening_equal,  le_int_wf,  bool_wf,  eqtt_to_assert,  assert_of_le_int,  eqff_to_assert,  equal_wf,  bool_cases_sqequal,  subtype_base_sq,  bool_subtype_base,  assert-bnot,  nat_plus_wf,  all_wf,  rmax_wf,  or_wf,  rpositive2_wf,  rpositive-iff,  rpositive_wf,  real_wf,  mul_preserves_le,  nat_plus_subtype_nat,  nat_plus_properties,  decidable__le,  satisfiable-full-omega-tt,  intformand_wf,  intformnot_wf,  intformle_wf,  itermVar_wf,  itermMultiply_wf,  int_formula_prop_and_lemma,  int_formula_prop_not_lemma,  int_formula_prop_le_lemma,  int_term_value_var_lemma,  int_term_value_mul_lemma,  int_formula_prop_wf,  mul_cancel_in_le,  less_than_wf,  multiply-is-int-iff,  false_wf
Rules used in proof :  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  lambdaFormation,  cut,  sqequalHypSubstitution,  unionElimination,  thin,  productElimination,  dependent_pairFormation,  hypothesisEquality,  hypothesis,  dependent_functionElimination,  independent_functionElimination,  sqequalRule,  applyEquality,  lambdaEquality,  imageElimination,  introduction,  extract_by_obid,  isectElimination,  equalityTransitivity,  equalitySymmetry,  intEquality,  setElimination,  rename,  multiplyEquality,  because_Cache,  natural_numberEquality,  imageMemberEquality,  baseClosed,  universeEquality,  independent_isectElimination,  equalityElimination,  promote_hyp,  instantiate,  cumulativity,  voidElimination,  functionEquality,  addLevel,  impliesFunctionality,  orFunctionality,  orLevelFunctionality,  int_eqEquality,  isect_memberEquality,  voidEquality,  independent_pairFormation,  computeAll,  dependent_set_memberEquality,  pointwiseFunctionality,  baseApply,  closedConclusion

Latex:
\mforall{}x,y:\mBbbR{}.    ((rpositive(x)  \mvee{}  rpositive(y))  {}\mRightarrow{}  rpositive(rmax(x;y)))



Date html generated: 2017_10_03-AM-08_24_20
Last ObjectModification: 2017_07_28-AM-07_23_16

Theory : reals


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