Nuprl Lemma : ratsign_wf

∀[x:ℤ × ℕ+]. (ratsign(x) ∈ {-1..2-})


Proof




Definitions occuring in Statement :  ratsign: ratsign(x),  int_seg: {i..j-},  nat_plus: ℕ+,  uall: ∀[x:A]. B[x],  member: t ∈ T,  product: x:A × B[x],  minus: -n,  natural_number: $n,  int: ℤ
Definitions unfolded in proof :  uall: ∀[x:A]. B[x],  member: t ∈ T,  ratsign: ratsign(x),  has-value: (a)↓,  uimplies: b supposing a,  top: Top,  pi1: fst(t),  all: ∀x:A. B[x],  implies: P ⇒ Q,  bool: 𝔹,  unit: Unit,  it: ⋅,  btrue: tt,  ifthenelse: if b then t else f fi ,  uiff: uiff(P;Q),  and: P ∧ Q,  int_seg: {i..j-},  lelt: i ≤ j < k,  decidable: Dec(P),  or: P ∨ Q,  not: ¬A,  satisfiable_int_formula: satisfiable_int_formula(fmla),  exists: ∃x:A. B[x],  prop: ℙ,  false: False,  bfalse: ff,  sq_type: SQType(T),  guard: {T},  bnot: ¬bb,  assert: ↑b,  rev_implies: P ⇐ Q,  iff: P ⇐⇒ Q
Lemmas referenced :  value-type-has-value,  int-value-type,  pi1_wf_top,  istype-void,  lt_int_wf,  eqtt_to_assert,  assert_of_lt_int,  decidable__le,  full-omega-unsat,  intformnot_wf,  intformle_wf,  itermConstant_wf,  istype-int,  int_formula_prop_not_lemma,  int_formula_prop_le_lemma,  int_term_value_constant_lemma,  int_formula_prop_wf,  decidable__lt,  intformless_wf,  int_formula_prop_less_lemma,  istype-le,  istype-less_than,  eqff_to_assert,  bool_cases_sqequal,  subtype_base_sq,  bool_wf,  bool_subtype_base,  assert-bnot,  iff_weakening_uiff,  assert_wf,  less_than_wf,  nat_plus_wf
Rules used in proof :  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  isect_memberFormation_alt,  introduction,  cut,  sqequalRule,  callbyvalueReduce,  extract_by_obid,  sqequalHypSubstitution,  isectElimination,  thin,  intEquality,  independent_isectElimination,  hypothesis,  productElimination,  independent_pairEquality,  hypothesisEquality,  isect_memberEquality_alt,  voidElimination,  closedConclusion,  natural_numberEquality,  because_Cache,  inhabitedIsType,  lambdaFormation_alt,  unionElimination,  equalityElimination,  dependent_set_memberEquality_alt,  minusEquality,  independent_pairFormation,  dependent_functionElimination,  approximateComputation,  independent_functionElimination,  dependent_pairFormation_alt,  lambdaEquality_alt,  universeIsType,  productIsType,  equalityTransitivity,  equalitySymmetry,  equalityIstype,  promote_hyp,  instantiate,  cumulativity,  axiomEquality

Latex:
\mforall{}[x:\mBbbZ{}  \mtimes{}  \mBbbN{}\msupplus{}].  (ratsign(x)  \mmember{}  \{-1..2\msupminus{}\})



Date html generated: 2019_10_30-AM-09_35_28
Last ObjectModification: 2019_01_17-AM-10_24_53

Theory : reals


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