Nuprl Lemma : isOdd-sum
∀[n:ℕ]. ∀[f:ℕn ⟶ ℤ].  uiff(↑isOdd(Σ(f[x] | x < n));↑isOdd(||filter(λx.isOdd(f[x]);upto(n))||))
Proof
Definitions occuring in Statement : 
isOdd: isOdd(n)
, 
upto: upto(n)
, 
sum: Σ(f[x] | x < k)
, 
length: ||as||
, 
filter: filter(P;l)
, 
int_seg: {i..j-}
, 
nat: ℕ
, 
assert: ↑b
, 
uiff: uiff(P;Q)
, 
uall: ∀[x:A]. B[x]
, 
so_apply: x[s]
, 
lambda: λx.A[x]
, 
function: x:A ⟶ B[x]
, 
natural_number: $n
, 
int: ℤ
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
, 
not: ¬A
, 
satisfiable_int_formula: satisfiable_int_formula(fmla)
, 
exists: ∃x:A. B[x]
, 
all: ∀x:A. B[x]
, 
top: Top
, 
and: P ∧ Q
, 
prop: ℙ
, 
uiff: uiff(P;Q)
, 
sum: Σ(f[x] | x < k)
, 
sum_aux: sum_aux(k;v;i;x.f[x])
, 
upto: upto(n)
, 
from-upto: [n, m)
, 
ifthenelse: if b then t else f fi 
, 
lt_int: i <z j
, 
bfalse: ff
, 
filter: filter(P;l)
, 
reduce: reduce(f;k;as)
, 
list_ind: list_ind, 
nil: []
, 
it: ⋅
, 
le: A ≤ B
, 
less_than': less_than'(a;b)
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
int_seg: {i..j-}
, 
lelt: i ≤ j < k
, 
decidable: Dec(P)
, 
or: P ∨ Q
, 
less_than: a < b
, 
squash: ↓T
, 
nat_plus: ℕ+
, 
sq_type: SQType(T)
, 
guard: {T}
, 
subtype_rel: A ⊆r B
, 
cand: A c∧ B
, 
iff: P 
⇐⇒ Q
, 
rev_implies: P 
⇐ Q
, 
subtract: n - m
, 
true: True
, 
bool: 𝔹
, 
unit: Unit
, 
btrue: tt
, 
assert: ↑b
, 
bnot: ¬bb
, 
same-parity: same-parity(n;m)
, 
isEven: isEven(n)
, 
eq_int: (i =z j)
, 
modulus: a mod n
, 
remainder: n rem m
, 
isOdd: isOdd(n)
Lemmas referenced : 
nat_properties, 
full-omega-unsat, 
intformand_wf, 
intformle_wf, 
itermConstant_wf, 
itermVar_wf, 
intformless_wf, 
istype-int, 
int_formula_prop_and_lemma, 
istype-void, 
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, 
istype-less_than, 
assert_witness, 
filter_nil_lemma, 
length_of_nil_lemma, 
isOdd_wf, 
istype-assert, 
int_seg_wf, 
length_wf, 
nil_wf, 
sum_wf, 
istype-le, 
subtract-1-ge-0, 
filter_wf5, 
upto_wf, 
int_seg_properties, 
decidable__le, 
intformnot_wf, 
int_formula_prop_not_lemma, 
decidable__lt, 
l_member_wf, 
istype-nat, 
upto_decomp1, 
filter_append_sq, 
filter_cons_lemma, 
sum_split1, 
subtype_base_sq, 
int_subtype_base, 
subtype_rel_function, 
subtract_wf, 
int_seg_subtype, 
istype-false, 
not-le-2, 
condition-implies-le, 
add-associates, 
minus-add, 
minus-one-mul, 
add-swap, 
minus-one-mul-top, 
add-mul-special, 
zero-mul, 
add-zero, 
add-commutes, 
le-add-cancel2, 
subtype_rel_self, 
itermSubtract_wf, 
int_term_value_subtract_lemma, 
length-append, 
length_wf_nat, 
same-parity_wf, 
eqtt_to_assert, 
same-parity-implies-even-odd, 
istype-true, 
ifthenelse_wf, 
list_wf, 
cons_wf, 
eqff_to_assert, 
bool_cases_sqequal, 
bool_wf, 
bool_subtype_base, 
assert-bnot, 
not-same-parity-implies-even-odd, 
iff_weakening_uiff, 
assert_wf, 
not_wf, 
isOdd-add, 
length_of_cons_lemma, 
odd-iff-not-even, 
isEven_wf, 
even-iff-not-odd
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation_alt, 
introduction, 
cut, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
hypothesisEquality, 
hypothesis, 
setElimination, 
rename, 
intWeakElimination, 
lambdaFormation_alt, 
natural_numberEquality, 
independent_isectElimination, 
approximateComputation, 
independent_functionElimination, 
dependent_pairFormation_alt, 
lambdaEquality_alt, 
int_eqEquality, 
dependent_functionElimination, 
isect_memberEquality_alt, 
voidElimination, 
sqequalRule, 
independent_pairFormation, 
universeIsType, 
productElimination, 
independent_pairEquality, 
isectIsTypeImplies, 
inhabitedIsType, 
functionIsTypeImplies, 
because_Cache, 
functionIsType, 
dependent_set_memberEquality_alt, 
applyEquality, 
unionElimination, 
productIsType, 
setIsType, 
imageElimination, 
instantiate, 
cumulativity, 
intEquality, 
equalityTransitivity, 
equalitySymmetry, 
addEquality, 
minusEquality, 
multiplyEquality, 
equalityElimination, 
isectIsType, 
equalityIstype, 
promote_hyp
Latex:
\mforall{}[n:\mBbbN{}].  \mforall{}[f:\mBbbN{}n  {}\mrightarrow{}  \mBbbZ{}].    uiff(\muparrow{}isOdd(\mSigma{}(f[x]  |  x  <  n));\muparrow{}isOdd(||filter(\mlambda{}x.isOdd(f[x]);upto(n))||))
Date html generated:
2020_05_19-PM-10_01_27
Last ObjectModification:
2019_11_12-PM-01_57_25
Theory : num_thy_1
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