Nuprl Lemma : sum_arith
∀[n:ℕ]. ∀[a,b:ℤ].  (Σ(a + (b * i) | i < n) = ((n * (a + a + (b * (n - 1)))) ÷ 2) ∈ ℤ)
Proof
Definitions occuring in Statement : 
sum: Σ(f[x] | x < k)
, 
nat: ℕ
, 
uall: ∀[x:A]. B[x]
, 
divide: n ÷ m
, 
multiply: n * m
, 
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
, 
so_lambda: λ2x.t[x]
, 
int_seg: {i..j-}
, 
nat: ℕ
, 
so_apply: x[s]
, 
true: True
, 
nequal: a ≠ b ∈ T 
, 
not: ¬A
, 
implies: P 
⇒ Q
, 
uimplies: b supposing a
, 
sq_type: SQType(T)
, 
all: ∀x:A. B[x]
, 
guard: {T}
, 
false: False
, 
prop: ℙ
, 
int_nzero: ℤ-o
, 
ge: i ≥ j 
, 
decidable: Dec(P)
, 
or: P ∨ Q
, 
uiff: uiff(P;Q)
, 
and: P ∧ Q
, 
satisfiable_int_formula: satisfiable_int_formula(fmla)
, 
exists: ∃x:A. B[x]
, 
top: Top
, 
subtype_rel: A ⊆r B
Lemmas referenced : 
sum_arith1, 
nat_wf, 
mul_cancel_in_eq, 
sum_wf, 
int_seg_wf, 
subtype_base_sq, 
int_subtype_base, 
equal-wf-base, 
nequal_wf, 
div_rem_sum, 
nat_properties, 
decidable__equal_int, 
add-is-int-iff, 
multiply-is-int-iff, 
full-omega-unsat, 
intformand_wf, 
intformnot_wf, 
intformeq_wf, 
itermMultiply_wf, 
itermConstant_wf, 
itermVar_wf, 
itermAdd_wf, 
itermSubtract_wf, 
int_formula_prop_and_lemma, 
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_term_value_add_lemma, 
int_term_value_subtract_lemma, 
int_formula_prop_wf, 
false_wf, 
mul-commutes, 
rem-exact
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
Error :isect_memberFormation_alt, 
introduction, 
cut, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
hypothesisEquality, 
hypothesis, 
Error :inhabitedIsType, 
sqequalRule, 
isect_memberEquality, 
axiomEquality, 
intEquality, 
Error :universeIsType, 
because_Cache, 
lambdaEquality, 
addEquality, 
multiplyEquality, 
setElimination, 
rename, 
natural_numberEquality, 
divideEquality, 
equalityTransitivity, 
equalitySymmetry, 
lambdaFormation, 
instantiate, 
cumulativity, 
independent_isectElimination, 
dependent_functionElimination, 
independent_functionElimination, 
voidElimination, 
baseClosed, 
dependent_set_memberEquality, 
unionElimination, 
pointwiseFunctionality, 
promote_hyp, 
baseApply, 
closedConclusion, 
productElimination, 
approximateComputation, 
dependent_pairFormation, 
int_eqEquality, 
voidEquality, 
independent_pairFormation, 
hyp_replacement, 
applyLambdaEquality, 
applyEquality
Latex:
\mforall{}[n:\mBbbN{}].  \mforall{}[a,b:\mBbbZ{}].    (\mSigma{}(a  +  (b  *  i)  |  i  <  n)  =  ((n  *  (a  +  a  +  (b  *  (n  -  1))))  \mdiv{}  2))
Date html generated:
2019_06_20-PM-01_18_12
Last ObjectModification:
2018_09_26-PM-02_38_30
Theory : int_2
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