Nuprl Lemma : gcd-non-neg

[y,x:ℕ].  (0 ≤ gcd(x;y))


Proof




Definitions occuring in Statement :  gcd: gcd(a;b) nat: uall: [x:A]. B[x] le: A ≤ B natural_number: $n
Definitions unfolded in proof :  uall: [x:A]. B[x] member: t ∈ T all: x:A. B[x] decidable: Dec(P) or: P ∨ Q le: A ≤ B and: P ∧ Q not: ¬A implies:  Q false: False nat: prop: uimplies: supposing a sq_type: SQType(T) guard: {T} gcd: gcd(a;b) eq_int: (i =z j) ifthenelse: if then else fi  btrue: tt ge: i ≥  satisfiable_int_formula: satisfiable_int_formula(fmla) exists: x:A. B[x] top: Top less_than': less_than'(a;b) nequal: a ≠ b ∈  int_upper: {i...} bool: 𝔹 unit: Unit it: uiff: uiff(P;Q) bfalse: ff bnot: ¬bb assert: b subtype_rel: A ⊆B int_nzero: -o so_lambda: λ2x.t[x] so_apply: x[s] less_than: a < b squash: T
Lemmas referenced :  decidable__equal_int less_than'_wf gcd_wf nat_wf subtype_base_sq int_subtype_base nat_properties decidable__le satisfiable-full-omega-tt intformand_wf intformnot_wf intformle_wf itermConstant_wf itermVar_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_wf int_upper_subtype_nat false_wf le_wf nequal-le-implies zero-add eq_int_wf bool_wf eqtt_to_assert assert_of_eq_int eqff_to_assert equal_wf bool_cases_sqequal bool_subtype_base assert-bnot neg_assert_of_eq_int zero-rem subtype_rel_sets nequal_wf int_upper_properties intformeq_wf int_formula_prop_eq_lemma equal-wf-base gcd-positive decidable__lt intformless_wf int_formula_prop_less_lemma
Rules used in proof :  sqequalSubstitution sqequalTransitivity computationStep sqequalReflexivity isect_memberFormation introduction cut extract_by_obid sqequalHypSubstitution dependent_functionElimination thin because_Cache natural_numberEquality hypothesis unionElimination sqequalRule productElimination independent_pairEquality lambdaEquality hypothesisEquality isectElimination setElimination rename axiomEquality equalityTransitivity equalitySymmetry isect_memberEquality voidElimination instantiate cumulativity intEquality independent_isectElimination independent_functionElimination dependent_pairFormation int_eqEquality voidEquality independent_pairFormation computeAll hypothesis_subsumption dependent_set_memberEquality lambdaFormation equalityElimination promote_hyp applyEquality setEquality applyLambdaEquality baseClosed imageElimination

Latex:
\mforall{}[y,x:\mBbbN{}].    (0  \mleq{}  gcd(x;y))



Date html generated: 2017_04_17-AM-09_45_50
Last ObjectModification: 2017_02_27-PM-05_40_34

Theory : num_thy_1


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