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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