Nuprl Lemma : int-sqrt-ext

x:ℕ(∃r:ℕ [(((r r) ≤ x) ∧ x < (r 1) (r 1))])


Proof




Definitions occuring in Statement :  nat: less_than: a < b le: A ≤ B all: x:A. B[x] sq_exists: x:A [B[x]] and: P ∧ Q multiply: m add: 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: λ2y.t[x; y] squash: T or: P ∨ Q guard: {T} prop: has-value: (a)↓ implies:  Q all: x:A. B[x] and: P ∧ Q strict4: strict4(F) uimplies: 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


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