Nuprl Lemma : exp-minusone

∀[n:ℕ]. ((-1)^n = if (n mod 2 =z 0) then 1 else -1 fi  ∈ ℤ)


Proof




Definitions occuring in Statement :  exp: i^n,  modulus: a mod n,  nat: ℕ,  ifthenelse: if b then t else f fi ,  eq_int: (i =z j),  uall: ∀[x:A]. B[x],  minus: -n,  natural_number: $n,  int: ℤ,  equal: s = t ∈ T
Definitions unfolded in proof :  uall: ∀[x:A]. B[x],  member: t ∈ T,  nat: ℕ,  implies: P ⇒ Q,  false: False,  ge: i ≥ j ,  uimplies: b supposing a,  satisfiable_int_formula: satisfiable_int_formula(fmla),  exists: ∃x:A. B[x],  not: ¬A,  all: ∀x:A. B[x],  top: Top,  and: P ∧ Q,  prop: ℙ,  squash: ↓T,  assert: ↑b,  ifthenelse: if b then t else f fi ,  eq_int: (i =z j),  modulus: a mod n,  btrue: tt,  true: True,  subtype_rel: A ⊆r B,  guard: {T},  iff: P ⇐⇒ Q,  rev_implies: P ⇐ Q,  decidable: Dec(P),  or: P ∨ Q,  exp: i^n,  bool: 𝔹,  unit: Unit,  it: ⋅,  uiff: uiff(P;Q),  bfalse: ff,  sq_type: SQType(T),  nat_plus: ℕ+,  less_than: a < b,  less_than': less_than'(a;b),  int_nzero: ℤ-o,  nequal: a ≠ b ∈ T ,  bnot: ¬bb
Lemmas referenced :  nat_properties,  satisfiable-full-omega-tt,  intformand_wf,  intformle_wf,  itermConstant_wf,  itermVar_wf,  intformless_wf,  int_formula_prop_and_lemma,  int_formula_prop_le_lemma,  int_term_value_constant_lemma,  int_term_value_var_lemma,  int_formula_prop_less_lemma,  int_formula_prop_wf,  ge_wf,  less_than_wf,  exp0_lemma,  equal_wf,  squash_wf,  true_wf,  ite_rw_true,  iff_weakening_equal,  decidable__le,  subtract_wf,  intformnot_wf,  itermSubtract_wf,  int_formula_prop_not_lemma,  int_term_value_subtract_lemma,  nat_wf,  primrec-unroll,  eq_int_wf,  bool_wf,  uiff_transitivity,  equal-wf-base,  int_subtype_base,  assert_wf,  eqtt_to_assert,  assert_of_eq_int,  intformeq_wf,  int_formula_prop_eq_lemma,  iff_transitivity,  bnot_wf,  not_wf,  iff_weakening_uiff,  eqff_to_assert,  assert_of_bnot,  subtype_base_sq,  add-one-mod-2,  subtract-add-cancel,  mod_bounds,  modulus_wf,  nequal_wf,  bool_cases_sqequal,  bool_subtype_base,  assert-bnot,  neg_assert_of_eq_int,  le_wf
Rules used in proof :  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  isect_memberFormation,  cut,  introduction,  extract_by_obid,  sqequalHypSubstitution,  isectElimination,  thin,  hypothesisEquality,  hypothesis,  setElimination,  rename,  intWeakElimination,  lambdaFormation,  natural_numberEquality,  independent_isectElimination,  dependent_pairFormation,  lambdaEquality,  int_eqEquality,  intEquality,  dependent_functionElimination,  isect_memberEquality,  voidElimination,  voidEquality,  sqequalRule,  independent_pairFormation,  computeAll,  independent_functionElimination,  axiomEquality,  applyEquality,  imageElimination,  equalityTransitivity,  equalitySymmetry,  universeEquality,  because_Cache,  minusEquality,  imageMemberEquality,  baseClosed,  productElimination,  unionElimination,  equalityElimination,  baseApply,  closedConclusion,  impliesFunctionality,  instantiate,  cumulativity,  dependent_set_memberEquality,  addLevel,  applyLambdaEquality,  promote_hyp,  productEquality

Latex:
\mforall{}[n:\mBbbN{}].  ((-1)\^{}n  =  if  (n  mod  2  =\msubz{}  0)  then  1  else  -1  fi  )



Date html generated: 2018_05_21-PM-01_05_15
Last ObjectModification: 2018_01_28-PM-02_01_49

Theory : num_thy_1


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