Nuprl Lemma : absval_mul

[x,y:ℤ].  (|x y| (|x| |y|) ∈ ℤ)


Proof




Definitions occuring in Statement :  absval: |i| uall: [x:A]. B[x] multiply: m int: equal: t ∈ T
Definitions unfolded in proof :  uall: [x:A]. B[x] member: t ∈ T all: x:A. B[x] implies:  Q bool: 𝔹 unit: Unit it: btrue: tt uiff: uiff(P;Q) and: P ∧ Q uimplies: supposing a less_than: a < b less_than': less_than'(a;b) top: Top true: True squash: T not: ¬A false: False bfalse: ff exists: x:A. B[x] subtype_rel: A ⊆B or: P ∨ Q sq_type: SQType(T) guard: {T} bnot: ¬bb ifthenelse: if then else fi  assert: b iff: ⇐⇒ Q rev_implies:  Q prop: le: A ≤ B nat: subtract: m nat_plus: + decidable: Dec(P) cand: c∧ B
Lemmas referenced :  absval_unfold2 lt_int_wf eqtt_to_assert assert_of_lt_int istype-top istype-void eqff_to_assert int_subtype_base bool_subtype_base bool_cases_sqequal subtype_base_sq iff_transitivity assert_wf bnot_wf not_wf less_than_wf iff_weakening_uiff assert_of_bnot istype-less_than istype-assert not-lt-2 minus-one-mul mul-associates istype-int minus-one-mul-top mul-swap one-mul bool_wf less_than_irreflexivity less_than_transitivity1 le_wf le_weakening2 mul_preserves_le mul-commutes zero-mul le-add-cancel zero-add add-associates add_functionality_wrt_le add-commutes add-zero minus-zero minus-add condition-implies-le less-iff-le mul_preserves_lt decidable__int_equal decidable__lt istype-false not-equal-2 add_functionality_wrt_lt le_reflexive add-mul-special
Rules used in proof :  sqequalSubstitution sqequalTransitivity computationStep sqequalReflexivity Error :isect_memberFormation_alt,  introduction cut sqequalRule extract_by_obid sqequalHypSubstitution isectElimination thin multiplyEquality hypothesisEquality hypothesis natural_numberEquality Error :inhabitedIsType,  Error :lambdaFormation_alt,  unionElimination equalityElimination equalityTransitivity equalitySymmetry productElimination independent_isectElimination because_Cache lessCases axiomSqEquality Error :isect_memberEquality_alt,  Error :isectIsTypeImplies,  independent_pairFormation voidElimination imageMemberEquality baseClosed imageElimination independent_functionElimination Error :dependent_pairFormation_alt,  Error :equalityIsType4,  baseApply closedConclusion applyEquality promote_hyp dependent_functionElimination instantiate Error :functionIsType,  Error :universeIsType,  Error :equalityIsType1,  minusEquality Error :lambdaEquality_alt,  cumulativity axiomEquality voidEquality isect_memberEquality dependent_set_memberEquality intEquality lambdaEquality addEquality

Latex:
\mforall{}[x,y:\mBbbZ{}].    (|x  *  y|  =  (|x|  *  |y|))



Date html generated: 2019_06_20-AM-11_24_38
Last ObjectModification: 2018_10_27-AM-11_38_11

Theory : arithmetic


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