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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