Nuprl Lemma : int-sqrt-ext

∀x:ℕ. (∃r:ℕ [(((r * r) ≤ x) ∧ x < (r + 1) * (r + 1))])


Proof




Definitions occuring in Statement :  nat: ℕ,  less_than: a < b,  le: A ≤ B,  all: ∀x:A. B[x],  sq_exists: ∃x:A [B[x]],  and: P ∧ Q,  multiply: n * m,  add: n + m,  natural_number: $n
Definitions unfolded in proof :  genrec-ap: genrec-ap,  decidable__less_than',  decidable__and,  iff_preserves_decidability,  decidable_functionality,  so_apply: x[s],  so_lambda: λ2x.t[x],  so_apply: x[s1;s2],  so_lambda: λ2x y.t[x; y],  squash: ↓T,  or: P ∨ Q,  guard: {T},  prop: ℙ,  has-value: (a)↓,  implies: P ⇒ Q,  all: ∀x:A. B[x],  and: P ∧ Q,  strict4: strict4(F),  uimplies: b supposing a,  top: Top,  so_apply: x[s1;s2;s3;s4],  so_lambda: so_lambda(x,y,z,w.t[x; y; z; w]),  uall: ∀[x:A]. B[x],  decidable__squash,  decidable__lt,  genrec: genrec,  natrec: natrec,  div_nat_induction-ext,  int-sq-root,  member: t ∈ T
Lemmas referenced :  lifting-strict-less,  lifting-strict-decide,  equal_wf,  top_wf,  is-exception_wf,  base_wf,  has-value_wf_base,  lifting-strict-spread,  int-sq-root,  decidable__less_than',  decidable__and,  iff_preserves_decidability,  decidable_functionality,  decidable__squash,  decidable__lt,  div_nat_induction-ext
Rules used in proof :  because_Cache,  decideExceptionCases,  independent_functionElimination,  dependent_functionElimination,  sqleReflexivity,  unionElimination,  unionEquality,  equalitySymmetry,  equalityTransitivity,  callbyvalueDecide,  inlFormation,  exceptionSqequal,  imageElimination,  imageMemberEquality,  inrFormation,  applyExceptionCases,  hypothesisEquality,  closedConclusion,  baseApply,  callbyvalueApply,  lambdaFormation,  independent_pairFormation,  independent_isectElimination,  voidEquality,  voidElimination,  isect_memberEquality,  baseClosed,  isectElimination,  sqequalHypSubstitution,  thin,  sqequalRule,  hypothesis,  extract_by_obid,  instantiate,  cut,  sqequalReflexivity,  computationStep,  sqequalTransitivity,  sqequalSubstitution,  introduction

Latex:
\mforall{}x:\mBbbN{}.  (\mexists{}r:\mBbbN{}  [(((r  *  r)  \mleq{}  x)  \mwedge{}  x  <  (r  +  1)  *  (r  +  1))])



Date html generated: 2018_05_21-PM-07_49_54
Last ObjectModification: 2018_05_19-AM-07_44_38

Theory : general


Home Index