Nuprl Lemma : exp-minus
∀[n:ℕ]. ∀[x:ℤ].  ((-x)^n = if (n mod 2 =z 0) then x^n else -x^n 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
, 
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
, 
uimplies: b supposing a
, 
bfalse: ff
, 
exists: ∃x:A. B[x]
, 
prop: ℙ
, 
or: P ∨ Q
, 
sq_type: SQType(T)
, 
guard: {T}
, 
bnot: ¬bb
, 
assert: ↑b
, 
false: False
, 
true: True
, 
nat: ℕ
, 
ge: i ≥ j 
, 
decidable: Dec(P)
, 
satisfiable_int_formula: satisfiable_int_formula(fmla)
, 
not: ¬A
, 
top: Top
, 
nequal: a ≠ b ∈ T 
, 
squash: ↓T
, 
subtype_rel: A ⊆r B
, 
iff: P 
⇐⇒ Q
, 
rev_implies: P 
⇐ Q
Lemmas referenced : 
minus-one-mul, 
exp_wf2, 
bool_wf, 
eqtt_to_assert, 
assert_of_eq_int, 
eqff_to_assert, 
equal_wf, 
bool_cases_sqequal, 
subtype_base_sq, 
bool_subtype_base, 
assert-bnot, 
neg_assert_of_eq_int, 
nat_properties, 
decidable__equal_int, 
le_wf, 
satisfiable-full-omega-tt, 
intformnot_wf, 
intformeq_wf, 
itermMultiply_wf, 
itermConstant_wf, 
itermVar_wf, 
int_formula_prop_not_lemma, 
int_formula_prop_eq_lemma, 
int_term_value_mul_lemma, 
int_term_value_constant_lemma, 
int_term_value_var_lemma, 
int_formula_prop_wf, 
itermMinus_wf, 
int_term_value_minus_lemma, 
squash_wf, 
true_wf, 
exp-of-mul, 
exp-minusone, 
iff_weakening_equal
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
introduction, 
cut, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
hypothesisEquality, 
hypothesis, 
because_Cache, 
sqequalRule, 
isect_memberEquality, 
axiomEquality, 
minusEquality, 
natural_numberEquality, 
lambdaFormation, 
unionElimination, 
equalityElimination, 
productElimination, 
independent_isectElimination, 
equalityTransitivity, 
equalitySymmetry, 
dependent_pairFormation, 
promote_hyp, 
dependent_functionElimination, 
instantiate, 
cumulativity, 
independent_functionElimination, 
voidElimination, 
setElimination, 
rename, 
dependent_set_memberEquality, 
lambdaEquality, 
int_eqEquality, 
intEquality, 
voidEquality, 
computeAll, 
applyEquality, 
imageElimination, 
universeEquality, 
multiplyEquality, 
imageMemberEquality, 
baseClosed
Latex:
\mforall{}[n:\mBbbN{}].  \mforall{}[x:\mBbbZ{}].    ((-x)\^{}n  =  if  (n  mod  2  =\msubz{}  0)  then  x\^{}n  else  -x\^{}n  fi  )
Date html generated:
2018_05_21-PM-01_05_21
Last ObjectModification:
2018_01_28-PM-02_01_53
Theory : num_thy_1
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