Nuprl Lemma : gcd-mod

∀x:ℕ+. ∀y:ℕ.  (gcd(x;y mod x) = gcd(x;y) ∈ ℤ)


Proof




Definitions occuring in Statement :  modulus: a mod n,  gcd: gcd(a;b),  nat_plus: ℕ+,  nat: ℕ,  all: ∀x:A. B[x],  int: ℤ,  equal: s = t ∈ T
Definitions unfolded in proof :  all: ∀x:A. B[x],  member: t ∈ T,  nat: ℕ,  decidable: Dec(P),  or: P ∨ Q,  uall: ∀[x:A]. B[x],  uimplies: b supposing a,  sq_type: SQType(T),  implies: P ⇒ Q,  guard: {T},  squash: ↓T,  prop: ℙ,  nat_plus: ℕ+,  int_seg: {i..j-},  lelt: i ≤ j < k,  and: P ∧ Q,  le: A ≤ B,  less_than': less_than'(a;b),  false: False,  not: ¬A,  ge: i ≥ j ,  satisfiable_int_formula: satisfiable_int_formula(fmla),  exists: ∃x:A. B[x],  top: Top,  true: True,  subtype_rel: A ⊆r B,  iff: P ⇐⇒ Q,  int_nzero: ℤ-o,  so_lambda: λ2x.t[x],  so_apply: x[s],  nequal: a ≠ b ∈ T ,  gcd: gcd(a;b),  int_upper: {i...},  bool: 𝔹,  unit: Unit,  it: ⋅,  btrue: tt,  uiff: uiff(P;Q),  ifthenelse: if b then t else f fi ,  bfalse: ff,  bnot: ¬bb,  assert: ↑b
Lemmas referenced :  decidable__equal_int,  subtype_base_sq,  int_subtype_base,  nat_wf,  nat_plus_wf,  gcd_wf,  squash_wf,  true_wf,  modulus_base,  false_wf,  nat_properties,  nat_plus_properties,  decidable__lt,  satisfiable-full-omega-tt,  intformand_wf,  intformnot_wf,  intformless_wf,  itermConstant_wf,  itermVar_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_formula_prop_wf,  lelt_wf,  equal_wf,  iff_weakening_equal,  modulus-is-rem,  subtype_rel_sets,  less_than_wf,  nequal_wf,  intformeq_wf,  int_formula_prop_eq_lemma,  equal-wf-base,  gcd_com,  nat_plus_subtype_nat,  int_upper_subtype_nat,  le_wf,  nequal-le-implies,  zero-add,  eq_int_wf,  bool_wf,  eqtt_to_assert,  assert_of_eq_int,  int_upper_properties,  eqff_to_assert,  bool_cases_sqequal,  bool_subtype_base,  assert-bnot,  neg_assert_of_eq_int
Rules used in proof :  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  lambdaFormation,  cut,  introduction,  extract_by_obid,  sqequalHypSubstitution,  dependent_functionElimination,  thin,  setElimination,  rename,  hypothesisEquality,  hypothesis,  natural_numberEquality,  unionElimination,  instantiate,  isectElimination,  cumulativity,  intEquality,  independent_isectElimination,  because_Cache,  independent_functionElimination,  applyEquality,  lambdaEquality,  imageElimination,  equalityTransitivity,  equalitySymmetry,  sqequalRule,  dependent_set_memberEquality,  independent_pairFormation,  dependent_pairFormation,  int_eqEquality,  isect_memberEquality,  voidElimination,  voidEquality,  computeAll,  universeEquality,  imageMemberEquality,  baseClosed,  productElimination,  setEquality,  applyLambdaEquality,  hypothesis_subsumption,  equalityElimination,  promote_hyp,  remainderEquality

Latex:
\mforall{}x:\mBbbN{}\msupplus{}.  \mforall{}y:\mBbbN{}.    (gcd(x;y  mod  x)  =  gcd(x;y))



Date html generated: 2018_05_21-PM-08_57_29
Last ObjectModification: 2017_07_26-PM-06_21_15

Theory : general


Home Index