Nuprl Lemma : absval_zero

∀[i:ℤ]. uiff(|i| = 0 ∈ ℤ;i = 0 ∈ ℤ)


Proof




Definitions occuring in Statement :  absval: |i|,  uiff: uiff(P;Q),  uall: ∀[x:A]. B[x],  natural_number: $n,  int: ℤ,  equal: s = t ∈ T
Definitions unfolded in proof :  uall: ∀[x:A]. B[x],  member: t ∈ T,  all: ∀x:A. B[x],  implies: P ⇒ Q,  bool: 𝔹,  unit: Unit,  it: ⋅,  btrue: tt,  uiff: uiff(P;Q),  and: P ∧ Q,  uimplies: b supposing a,  less_than: a < b,  less_than': less_than'(a;b),  top: Top,  true: True,  squash: ↓T,  not: ¬A,  false: False,  prop: ℙ,  subtype_rel: A ⊆r B,  bfalse: ff,  exists: ∃x:A. B[x],  or: P ∨ Q,  sq_type: SQType(T),  guard: {T},  bnot: ¬bb,  ifthenelse: if b then t else f fi ,  assert: ↑b,  iff: P ⇐⇒ Q,  rev_implies: P ⇐ Q
Lemmas referenced :  absval_unfold2,  lt_int_wf,  bool_wf,  eqtt_to_assert,  assert_of_lt_int,  top_wf,  less_than_wf,  equal-wf-base,  int_subtype_base,  eqff_to_assert,  equal_wf,  bool_cases_sqequal,  subtype_base_sq,  bool_subtype_base,  iff_transitivity,  assert_wf,  bnot_wf,  not_wf,  iff_weakening_uiff,  assert_of_bnot,  minus-one-mul,  add-commutes,  minus-one-mul-top,  add-mul-special,  zero-mul,  zero-add,  minus-zero
Rules used in proof :  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  isect_memberFormation,  introduction,  cut,  sqequalRule,  extract_by_obid,  sqequalHypSubstitution,  isectElimination,  thin,  hypothesisEquality,  hypothesis,  natural_numberEquality,  lambdaFormation,  unionElimination,  equalityElimination,  equalityTransitivity,  equalitySymmetry,  productElimination,  independent_isectElimination,  because_Cache,  lessCases,  sqequalAxiom,  isect_memberEquality,  independent_pairFormation,  voidElimination,  voidEquality,  imageMemberEquality,  baseClosed,  imageElimination,  independent_functionElimination,  intEquality,  applyEquality,  dependent_pairFormation,  promote_hyp,  dependent_functionElimination,  instantiate,  cumulativity,  impliesFunctionality,  independent_pairEquality,  axiomEquality,  baseApply,  closedConclusion,  addEquality,  lambdaEquality,  minusEquality

Latex:
\mforall{}[i:\mBbbZ{}].  uiff(|i|  =  0;i  =  0)



Date html generated: 2017_04_14-AM-07_17_01
Last ObjectModification: 2017_02_27-PM-02_51_43

Theory : arithmetic


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