Nuprl Lemma : sum-consecutive-squares
∀[n:ℕ]. (Σ(i * i | i < n) = (((n - 1) * n * ((2 * n) - 1)) ÷ 6) ∈ 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
, 
natural_number: $n
, 
int: ℤ
, 
equal: s = t ∈ T
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
uimplies: b supposing a
, 
sq_type: SQType(T)
, 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
guard: {T}
, 
squash: ↓T
, 
prop: ℙ
, 
so_lambda: λ2x.t[x]
, 
int_seg: {i..j-}
, 
nat: ℕ
, 
so_apply: x[s]
, 
int_nzero: ℤ-o
, 
true: True
, 
nequal: a ≠ b ∈ T 
, 
not: ¬A
, 
false: False
, 
subtype_rel: A ⊆r B
, 
iff: P 
⇐⇒ Q
, 
and: P ∧ Q
, 
rev_implies: P 
⇐ Q
Lemmas referenced : 
sum-of-consecutive-squares, 
subtype_base_sq, 
int_subtype_base, 
equal_wf, 
squash_wf, 
true_wf, 
sum_wf, 
int_seg_wf, 
divide-exact, 
equal-wf-base, 
nequal_wf, 
iff_weakening_equal, 
nat_wf
Rules used in proof : 
cut, 
introduction, 
extract_by_obid, 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
hypothesis, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
hypothesisEquality, 
instantiate, 
cumulativity, 
intEquality, 
independent_isectElimination, 
dependent_functionElimination, 
equalityTransitivity, 
equalitySymmetry, 
independent_functionElimination, 
applyEquality, 
lambdaEquality, 
imageElimination, 
universeEquality, 
sqequalRule, 
multiplyEquality, 
setElimination, 
rename, 
because_Cache, 
natural_numberEquality, 
dependent_set_memberEquality, 
addLevel, 
lambdaFormation, 
voidElimination, 
baseClosed, 
imageMemberEquality, 
productElimination
Latex:
\mforall{}[n:\mBbbN{}].  (\mSigma{}(i  *  i  |  i  <  n)  =  (((n  -  1)  *  n  *  ((2  *  n)  -  1))  \mdiv{}  6))
Date html generated:
2017_04_14-AM-09_21_34
Last ObjectModification:
2017_02_27-PM-03_57_20
Theory : int_2
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