Nuprl Lemma : rpositive-rmul

∀x,y:ℝ.  (rpositive(x) ⇒ rpositive(y) ⇒ rpositive(x * y))


Proof




Definitions occuring in Statement :  rpositive: rpositive(x),  rmul: a * b,  real: ℝ,  all: ∀x:A. B[x],  implies: P ⇒ Q
Definitions unfolded in proof :  all: ∀x:A. B[x],  implies: P ⇒ Q,  rmul: a * b,  has-value: (a)↓,  uall: ∀[x:A]. B[x],  member: t ∈ T,  nat_plus: ℕ+,  subtype_rel: A ⊆r B,  int_upper: {i...},  so_lambda: λ2x.t[x],  real: ℝ,  so_apply: x[s],  prop: ℙ,  iff: P ⇐⇒ Q,  and: P ∧ Q,  rev_implies: P ⇐ Q,  rpositive2: rpositive2(x),  exists: ∃x:A. B[x],  nat: ℕ,  true: True,  bool: 𝔹,  unit: Unit,  it: ⋅,  btrue: tt,  uiff: uiff(P;Q),  uimplies: b supposing a,  ifthenelse: if b then t else f fi ,  le: A ≤ B,  less_than': less_than'(a;b),  false: False,  not: ¬A,  less_than: a < b,  squash: ↓T,  guard: {T},  decidable: Dec(P),  or: P ∨ Q,  satisfiable_int_formula: satisfiable_int_formula(fmla),  top: Top,  bfalse: ff,  sq_type: SQType(T),  bnot: ¬bb,  assert: ↑b,  cand: A c∧ B,  reg-seq-mul: reg-seq-mul(x;y),  nequal: a ≠ b ∈ T ,  int_nzero: ℤ-o,  sq_stable: SqStable(P),  rev_uimplies: rev_uimplies(P;Q),  ge: i ≥ j ,  gt: i > j
Lemmas referenced :  real-has-value,  rpositive2_functionality,  accelerate_wf,  imax_wf,  canonical-bound_wf,  int_upper_wf,  all_wf,  nat_plus_wf,  le_wf,  absval_wf,  less_than_wf,  reg-seq-mul_wf2,  reg-seq-mul_wf,  accelerate-bdd-diff,  rpositive2_wf,  rpositive-iff,  rmul_wf,  rpositive_wf,  real_wf,  nat_wf,  ifthenelse_wf,  le_int_wf,  bool_wf,  eqtt_to_assert,  assert_of_le_int,  add_nat_plus,  multiply_nat_wf,  subtype_rel_set,  int_upper_subtype_nat,  false_wf,  nat_plus_properties,  decidable__lt,  satisfiable-full-omega-tt,  intformand_wf,  intformnot_wf,  intformless_wf,  itermConstant_wf,  itermVar_wf,  itermAdd_wf,  itermMultiply_wf,  intformeq_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_term_value_add_lemma,  int_term_value_mul_lemma,  int_formula_prop_eq_lemma,  int_formula_prop_wf,  equal_wf,  eqff_to_assert,  bool_cases_sqequal,  subtype_base_sq,  bool_subtype_base,  assert-bnot,  add-is-int-iff,  multiply-is-int-iff,  squash_wf,  true_wf,  add_functionality_wrt_eq,  imax_unfold,  iff_weakening_equal,  imax_nat_plus,  multiply_nat_plus,  imax_ub,  decidable__le,  intformle_wf,  int_formula_prop_le_lemma,  mul_nat_plus,  mul_preserves_le,  nat_plus_subtype_nat,  mul_preserves_lt,  mul_cancel_in_le,  equal-wf-base,  mul-swap,  div_rem_sum2,  nequal_wf,  left_mul_subtract_distrib,  rem_bounds_absval,  set_wf,  int_subtype_base,  decidable__equal_int,  sq_stable__less_than,  le_functionality,  le_weakening,  multiply_functionality_wrt_le,  sq_stable__le,  absval_pos,  neg_mul_arg_bounds,  gt_wf,  mul_bounds_1a,  subtract_wf,  itermSubtract_wf,  int_term_value_subtract_lemma
Rules used in proof :  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  lambdaFormation,  cut,  sqequalRule,  callbyvalueReduce,  introduction,  extract_by_obid,  sqequalHypSubstitution,  isectElimination,  thin,  hypothesisEquality,  hypothesis,  dependent_functionElimination,  dependent_set_memberEquality,  addEquality,  multiplyEquality,  natural_numberEquality,  applyEquality,  lambdaEquality,  setElimination,  rename,  setEquality,  because_Cache,  independent_functionElimination,  productElimination,  addLevel,  impliesFunctionality,  functionEquality,  intEquality,  unionElimination,  equalityElimination,  equalityTransitivity,  equalitySymmetry,  independent_isectElimination,  independent_pairFormation,  imageMemberEquality,  baseClosed,  applyLambdaEquality,  dependent_pairFormation,  int_eqEquality,  isect_memberEquality,  voidElimination,  voidEquality,  computeAll,  promote_hyp,  instantiate,  cumulativity,  pointwiseFunctionality,  baseApply,  closedConclusion,  imageElimination,  universeEquality,  inlFormation,  inrFormation,  productEquality,  divideEquality,  remainderEquality

Latex:
\mforall{}x,y:\mBbbR{}.    (rpositive(x)  {}\mRightarrow{}  rpositive(y)  {}\mRightarrow{}  rpositive(x  *  y))



Date html generated: 2017_10_03-AM-08_23_29
Last ObjectModification: 2017_07_28-AM-07_22_53

Theory : reals


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