Nuprl Lemma : divisibility-by-2-rule
∀n:ℕ+. ∀a:ℕn ⟶ ℤ.  (2 | Σi<n.a[i]*10^i 
⇐⇒ 2 | a[0])
Proof
Definitions occuring in Statement : 
power-sum: Σi<n.a[i]*x^i
, 
divides: b | a
, 
int_seg: {i..j-}
, 
nat_plus: ℕ+
, 
so_apply: x[s]
, 
all: ∀x:A. B[x]
, 
iff: P 
⇐⇒ Q
, 
function: x:A ⟶ B[x]
, 
natural_number: $n
, 
int: ℤ
Definitions unfolded in proof : 
all: ∀x:A. B[x]
, 
member: t ∈ T
, 
uall: ∀[x:A]. B[x]
, 
nat_plus: ℕ+
, 
eqmod: a ≡ b mod m
, 
divides: b | a
, 
exists: ∃x:A. B[x]
, 
decidable: Dec(P)
, 
or: P ∨ Q
, 
uimplies: b supposing a
, 
not: ¬A
, 
implies: P 
⇒ Q
, 
satisfiable_int_formula: satisfiable_int_formula(fmla)
, 
top: Top
, 
subtract: n - m
, 
prop: ℙ
, 
false: False
, 
subtype_rel: A ⊆r B
, 
power-sum: Σi<n.a[i]*x^i
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
int_seg: {i..j-}
, 
lelt: i ≤ j < k
, 
and: P ∧ Q
, 
le: A ≤ B
, 
less_than': less_than'(a;b)
, 
rev_implies: P 
⇐ Q
, 
iff: P 
⇐⇒ Q
, 
sq_type: SQType(T)
, 
guard: {T}
, 
squash: ↓T
, 
true: True
, 
nat: ℕ
, 
bool: 𝔹
, 
unit: Unit
, 
it: ⋅
, 
btrue: tt
, 
uiff: uiff(P;Q)
, 
ifthenelse: if b then t else f fi 
, 
bfalse: ff
, 
bnot: ¬bb
, 
assert: ↑b
, 
nequal: a ≠ b ∈ T 
Lemmas referenced : 
int_seg_wf, 
istype-int, 
nat_plus_wf, 
nat_plus_properties, 
decidable__equal_int, 
full-omega-unsat, 
intformnot_wf, 
intformeq_wf, 
itermSubtract_wf, 
itermConstant_wf, 
itermMultiply_wf, 
int_formula_prop_not_lemma, 
istype-void, 
int_formula_prop_eq_lemma, 
int_term_value_subtract_lemma, 
int_term_value_constant_lemma, 
int_term_value_mul_lemma, 
int_formula_prop_wf, 
int_subtype_base, 
power-sum_wf, 
nat_plus_subtype_nat, 
eqmod_wf, 
istype-false, 
decidable__lt, 
intformand_wf, 
intformless_wf, 
itermVar_wf, 
int_formula_prop_and_lemma, 
int_formula_prop_less_lemma, 
int_term_value_var_lemma, 
le_wf, 
less_than_wf, 
eqmod_functionality_wrt_eqmod, 
power-sum_functionality_wrt_eqmod, 
eqmod_weakening, 
subtype_base_sq, 
isolate_summand, 
exp_wf2, 
int_seg_subtype_nat, 
equal_wf, 
squash_wf, 
true_wf, 
istype-universe, 
subtype_rel_self, 
iff_weakening_equal, 
exp0_lemma, 
sum_wf, 
nat_wf, 
eq_int_wf, 
eqtt_to_assert, 
assert_of_eq_int, 
eqff_to_assert, 
set_subtype_base, 
lelt_wf, 
bool_cases_sqequal, 
bool_subtype_base, 
assert-bnot, 
neg_assert_of_eq_int, 
zero_ann_a, 
exp-zero, 
not-lt-2, 
not-equal-2, 
add_functionality_wrt_le, 
add-associates, 
add-zero, 
zero-add, 
le-add-cancel, 
condition-implies-le, 
add-commutes, 
minus-add, 
minus-zero, 
itermAdd_wf, 
int_term_value_add_lemma, 
add_functionality_wrt_eq, 
sum_constant, 
divides_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation_alt, 
cut, 
functionIsType, 
universeIsType, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
natural_numberEquality, 
setElimination, 
rename, 
hypothesisEquality, 
hypothesis, 
dependent_pairFormation_alt, 
dependent_functionElimination, 
because_Cache, 
unionElimination, 
independent_isectElimination, 
approximateComputation, 
independent_functionElimination, 
lambdaEquality_alt, 
isect_memberEquality_alt, 
voidElimination, 
sqequalRule, 
equalityIsType4, 
inhabitedIsType, 
baseClosed, 
baseApply, 
closedConclusion, 
applyEquality, 
dependent_set_memberEquality_alt, 
independent_pairFormation, 
int_eqEquality, 
productIsType, 
productElimination, 
promote_hyp, 
instantiate, 
cumulativity, 
intEquality, 
equalityTransitivity, 
equalitySymmetry, 
multiplyEquality, 
imageElimination, 
universeEquality, 
imageMemberEquality, 
equalityElimination, 
equalityIsType2, 
inrFormation_alt, 
addEquality, 
minusEquality, 
equalityIsType1
Latex:
\mforall{}n:\mBbbN{}\msupplus{}.  \mforall{}a:\mBbbN{}n  {}\mrightarrow{}  \mBbbZ{}.    (2  |  \mSigma{}i<n.a[i]*10\^{}i  \mLeftarrow{}{}\mRightarrow{}  2  |  a[0])
Date html generated:
2019_10_15-AM-11_25_58
Last ObjectModification:
2018_10_09-PM-00_15_01
Theory : general
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