Nuprl Lemma : isolate_summand
∀[n:ℕ]. ∀[f:ℕn ⟶ ℤ]. ∀[m:ℕn].  (Σ(f[x] | x < n) = (f[m] + Σ(if (x =z m) then 0 else f[x] fi  | x < n)) ∈ ℤ)
Proof
Definitions occuring in Statement : 
sum: Σ(f[x] | x < k), 
int_seg: {i..j-}, 
nat: ℕ, 
ifthenelse: if b then t else f fi , 
eq_int: (i =z j), 
uall: ∀[x:A]. B[x], 
so_apply: x[s], 
function: x:A ⟶ B[x], 
add: n + m, 
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, 
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, 
guard: {T}, 
int_seg: {i..j-}, 
lelt: i ≤ j < k, 
decidable: Dec(P), 
or: P ∨ Q, 
subtype_rel: A ⊆r B, 
le: A ≤ B, 
less_than': less_than'(a;b), 
iff: P ⇐⇒ Q, 
rev_implies: P ⇐ Q, 
uiff: uiff(P;Q), 
subtract: n - m, 
true: True, 
sq_type: SQType(T), 
bool: 𝔹, 
unit: Unit, 
it: ⋅, 
btrue: tt, 
less_than: a < b, 
squash: ↓T, 
bfalse: ff, 
bnot: ¬bb, 
ifthenelse: if b then t else f fi , 
assert: ↑b, 
nequal: a ≠ b ∈ T , 
so_lambda: λ2x.t[x], 
so_apply: x[s]
Lemmas referenced : 
nat_properties, 
full-omega-unsat, 
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, 
int_seg_wf, 
int_seg_properties, 
decidable__le, 
subtract_wf, 
intformnot_wf, 
itermSubtract_wf, 
int_formula_prop_not_lemma, 
int_term_value_subtract_lemma, 
subtype_rel_function, 
int_seg_subtype, 
false_wf, 
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, 
nat_wf, 
decidable__equal_int, 
subtype_base_sq, 
int_subtype_base, 
lt_int_wf, 
bool_wf, 
eqtt_to_assert, 
assert_of_lt_int, 
top_wf, 
eq_int_wf, 
assert_of_eq_int, 
eqff_to_assert, 
equal_wf, 
bool_cases_sqequal, 
bool_subtype_base, 
assert-bnot, 
neg_assert_of_eq_int, 
intformeq_wf, 
int_formula_prop_eq_lemma, 
not_functionality_wrt_uiff, 
assert_wf, 
sum-unroll, 
decidable__lt, 
lelt_wf, 
itermAdd_wf, 
int_term_value_add_lemma, 
sum_functionality, 
le_wf, 
add-is-int-iff
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
Error :isect_memberFormation_alt, 
introduction, 
cut, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
hypothesisEquality, 
hypothesis, 
setElimination, 
rename, 
intWeakElimination, 
lambdaFormation, 
natural_numberEquality, 
independent_isectElimination, 
approximateComputation, 
independent_functionElimination, 
dependent_pairFormation, 
lambdaEquality, 
int_eqEquality, 
intEquality, 
dependent_functionElimination, 
isect_memberEquality, 
voidElimination, 
voidEquality, 
sqequalRule, 
independent_pairFormation, 
axiomEquality, 
functionEquality, 
because_Cache, 
productElimination, 
Error :universeIsType, 
Error :functionIsType, 
Error :inhabitedIsType, 
unionElimination, 
applyEquality, 
addEquality, 
minusEquality, 
multiplyEquality, 
instantiate, 
cumulativity, 
equalityTransitivity, 
equalitySymmetry, 
equalityElimination, 
lessCases, 
axiomSqEquality, 
imageMemberEquality, 
baseClosed, 
imageElimination, 
promote_hyp, 
dependent_set_memberEquality, 
functionExtensionality, 
pointwiseFunctionality, 
baseApply, 
closedConclusion
Latex:
\mforall{}[n:\mBbbN{}].  \mforall{}[f:\mBbbN{}n  {}\mrightarrow{}  \mBbbZ{}].  \mforall{}[m:\mBbbN{}n].
    (\mSigma{}(f[x]  |  x  <  n)  =  (f[m]  +  \mSigma{}(if  (x  =\msubz{}  m)  then  0  else  f[x]  fi    |  x  <  n)))
Date html generated:
2019_06_20-PM-01_18_23
Last ObjectModification:
2018_09_26-PM-02_40_38
Theory : int_2
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