Nuprl Lemma : sum_split1
∀[n:ℕ+]. ∀[f:ℕn ⟶ ℤ].  (Σ(f[x] | x < n) = (Σ(f[x] | x < n - 1) + f[n - 1]) ∈ ℤ)
Proof
Definitions occuring in Statement : 
sum: Σ(f[x] | x < k), 
int_seg: {i..j-}, 
nat_plus: ℕ+, 
uall: ∀[x:A]. B[x], 
so_apply: x[s], 
function: x:A ⟶ B[x], 
subtract: n - m, 
add: n + m, 
natural_number: $n, 
int: ℤ, 
equal: s = t ∈ T
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x], 
member: t ∈ T, 
subtype_rel: A ⊆r B, 
so_lambda: λ2x.t[x], 
so_apply: x[s], 
nat_plus: ℕ+, 
nat: ℕ, 
all: ∀x:A. B[x], 
decidable: Dec(P), 
or: P ∨ Q, 
uimplies: b supposing a, 
satisfiable_int_formula: satisfiable_int_formula(fmla), 
exists: ∃x:A. B[x], 
false: False, 
implies: P ⇒ Q, 
not: ¬A, 
top: Top, 
and: P ∧ Q, 
prop: ℙ, 
int_seg: {i..j-}, 
lelt: i ≤ j < k, 
le: A ≤ B, 
less_than: a < b, 
bool: 𝔹, 
unit: Unit, 
it: ⋅, 
btrue: tt, 
uiff: uiff(P;Q), 
ifthenelse: if b then t else f fi , 
bfalse: ff, 
sq_type: SQType(T), 
guard: {T}, 
bnot: ¬bb, 
assert: ↑b, 
nequal: a ≠ b ∈ T 
Lemmas referenced : 
sum-as-primrec, 
nat_plus_subtype_nat, 
int_seg_wf, 
subtract_wf, 
nat_plus_properties, 
decidable__le, 
satisfiable-full-omega-tt, 
intformand_wf, 
intformnot_wf, 
intformle_wf, 
itermConstant_wf, 
itermSubtract_wf, 
itermVar_wf, 
intformless_wf, 
int_formula_prop_and_lemma, 
int_formula_prop_not_lemma, 
int_formula_prop_le_lemma, 
int_term_value_constant_lemma, 
int_term_value_subtract_lemma, 
int_term_value_var_lemma, 
int_formula_prop_less_lemma, 
int_formula_prop_wf, 
le_wf, 
decidable__lt, 
lelt_wf, 
primrec-unroll, 
eq_int_wf, 
bool_wf, 
eqtt_to_assert, 
assert_of_eq_int, 
intformeq_wf, 
int_formula_prop_eq_lemma, 
eqff_to_assert, 
equal_wf, 
bool_cases_sqequal, 
subtype_base_sq, 
bool_subtype_base, 
assert-bnot, 
neg_assert_of_eq_int, 
primrec_wf, 
decidable__equal_int, 
nat_plus_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
introduction, 
cut, 
sqequalRule, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
hypothesisEquality, 
applyEquality, 
hypothesis, 
lambdaEquality, 
functionExtensionality, 
natural_numberEquality, 
setElimination, 
rename, 
because_Cache, 
dependent_set_memberEquality, 
dependent_functionElimination, 
unionElimination, 
independent_isectElimination, 
dependent_pairFormation, 
int_eqEquality, 
intEquality, 
isect_memberEquality, 
voidElimination, 
voidEquality, 
independent_pairFormation, 
computeAll, 
productElimination, 
lambdaFormation, 
equalityElimination, 
equalityTransitivity, 
equalitySymmetry, 
promote_hyp, 
instantiate, 
cumulativity, 
independent_functionElimination, 
addEquality, 
functionEquality, 
axiomEquality
Latex:
\mforall{}[n:\mBbbN{}\msupplus{}].  \mforall{}[f:\mBbbN{}n  {}\mrightarrow{}  \mBbbZ{}].    (\mSigma{}(f[x]  |  x  <  n)  =  (\mSigma{}(f[x]  |  x  <  n  -  1)  +  f[n  -  1]))
Date html generated:
2017_04_14-AM-09_21_19
Last ObjectModification:
2017_02_27-PM-03_57_23
Theory : int_2
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