Nuprl Lemma : mul-div-bounds

∀[a,b:ℤ]. ∀[m:ℤ-o].  (|(a * (b ÷ m)) - b * (a ÷ m)| ≤ (|a| + |b|))


Proof




Definitions occuring in Statement :  absval: |i|,  int_nzero: ℤ-o,  uall: ∀[x:A]. B[x],  le: A ≤ B,  divide: n ÷ m,  multiply: n * m,  subtract: n - m,  add: n + m,  int: ℤ
Definitions unfolded in proof :  rev_uimplies: rev_uimplies(P;Q),  ge: i ≥ j ,  less_than: a < b,  le: A ≤ B,  sq_type: SQType(T),  uiff: uiff(P;Q),  or: P ∨ Q,  decidable: Dec(P),  rev_implies: P ⇐ Q,  iff: P ⇐⇒ Q,  guard: {T},  true: True,  nat: ℕ,  squash: ↓T,  subtype_rel: A ⊆r B,  prop: ℙ,  and: P ∧ Q,  top: Top,  all: ∀x:A. B[x],  false: False,  exists: ∃x:A. B[x],  satisfiable_int_formula: satisfiable_int_formula(fmla),  implies: P ⇒ Q,  not: ¬A,  int_nzero: ℤ-o,  nequal: a ≠ b ∈ T ,  uimplies: b supposing a,  member: t ∈ T,  uall: ∀[x:A]. B[x]
Lemmas referenced :  le_weakening,  add_functionality_wrt_le,  int-triangle-inequality2,  le_transitivity,  le_functionality,  nat_properties,  equal-wf-base,  mul_preserves_le,  int_formula_prop_less_lemma,  int_formula_prop_le_lemma,  intformless_wf,  intformle_wf,  decidable__le,  rem_bounds_absval,  int_nzero_wf,  less_than'_wf,  false_wf,  int_term_value_add_lemma,  int_term_value_subtract_lemma,  int_term_value_mul_lemma,  itermAdd_wf,  itermSubtract_wf,  itermMultiply_wf,  multiply-is-int-iff,  add-is-int-iff,  decidable__equal_int,  int_subtype_base,  subtype_base_sq,  iff_weakening_equal,  nat_wf,  absval_mul,  true_wf,  squash_wf,  le_wf,  equal-wf-T-base,  absval_nat_plus,  int_formula_prop_wf,  int_formula_prop_not_lemma,  int_term_value_constant_lemma,  int_term_value_var_lemma,  int_formula_prop_eq_lemma,  int_formula_prop_and_lemma,  intformnot_wf,  itermConstant_wf,  itermVar_wf,  intformeq_wf,  intformand_wf,  full-omega-unsat,  int_nzero_properties,  subtract_wf,  absval_wf,  mul_cancel_in_le,  mul_preserves_eq,  div_rem_sum
Rules used in proof :  applyLambdaEquality,  remainderEquality,  axiomEquality,  independent_pairEquality,  closedConclusion,  baseApply,  promote_hyp,  pointwiseFunctionality,  unionElimination,  cumulativity,  instantiate,  productElimination,  universeEquality,  imageMemberEquality,  imageElimination,  baseClosed,  addEquality,  applyEquality,  independent_pairFormation,  sqequalRule,  voidEquality,  voidElimination,  isect_memberEquality,  dependent_functionElimination,  intEquality,  int_eqEquality,  lambdaEquality,  dependent_pairFormation,  independent_functionElimination,  approximateComputation,  natural_numberEquality,  lambdaFormation,  rename,  setElimination,  divideEquality,  multiplyEquality,  independent_isectElimination,  hypothesis,  equalitySymmetry,  equalityTransitivity,  because_Cache,  hypothesisEquality,  thin,  isectElimination,  sqequalHypSubstitution,  extract_by_obid,  cut,  introduction,  isect_memberFormation,  sqequalReflexivity,  computationStep,  sqequalTransitivity,  sqequalSubstitution

Latex:
\mforall{}[a,b:\mBbbZ{}].  \mforall{}[m:\mBbbZ{}\msupminus{}\msupzero{}].    (|(a  *  (b  \mdiv{}  m))  -  b  *  (a  \mdiv{}  m)|  \mleq{}  (|a|  +  |b|))



Date html generated: 2017_09_29-PM-05_57_31
Last ObjectModification: 2017_09_06-PM-01_47_38

Theory : int_2


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