Nuprl Lemma : cantor-interval-length

[a,b:ℝ]. ∀[n:ℕ]. ∀[f:ℕn ⟶ 𝔹].  (((snd(cantor-interval(a;b;f;n))) fst(cantor-interval(a;b;f;n))) (2^n a)/3^n)


Proof




Definitions occuring in Statement :  cantor-interval: cantor-interval(a;b;f;n) int-rdiv: (a)/k1 int-rmul: k1 a rsub: y req: y real: exp: i^n int_seg: {i..j-} nat: bool: 𝔹 uall: [x:A]. B[x] pi1: fst(t) pi2: snd(t) function: x:A ⟶ B[x] natural_number: $n
Definitions unfolded in proof :  uall: [x:A]. B[x] member: t ∈ T nat: implies:  Q false: False ge: i ≥  uimplies: supposing a not: ¬A satisfiable_int_formula: satisfiable_int_formula(fmla) exists: x:A. B[x] all: x:A. B[x] top: Top and: P ∧ Q prop: cantor-interval: cantor-interval(a;b;f;n) decidable: Dec(P) or: P ∨ Q pi2: snd(t) pi1: fst(t) int_nzero: -o nequal: a ≠ b ∈  int_seg: {i..j-} lelt: i ≤ j < k subtype_rel: A ⊆B le: A ≤ B less_than': less_than'(a;b) iff: ⇐⇒ Q rev_implies:  Q uiff: uiff(P;Q) subtract: m true: True sq_stable: SqStable(P) squash: T nat_plus: + less_than: a < b rneq: x ≠ y guard: {T} rless: x < y sq_exists: x:A [B[x]] so_lambda: λ2x.t[x] so_apply: x[s] rev_uimplies: rev_uimplies(P;Q) sq_type: SQType(T) lt_int: i <j ifthenelse: if then else fi  btrue: tt bool: 𝔹 unit: Unit it: bfalse: ff bnot: ¬bb assert: b rdiv: (x/y) req_int_terms: t1 ≡ t2
Lemmas referenced :  nat_properties full-omega-unsat intformand_wf intformle_wf itermConstant_wf itermVar_wf intformless_wf istype-int int_formula_prop_and_lemma istype-void int_formula_prop_le_lemma int_term_value_constant_lemma int_term_value_var_lemma int_formula_prop_less_lemma int_formula_prop_wf ge_wf istype-less_than req_witness rsub_wf cantor-interval_wf decidable__le intformnot_wf int_formula_prop_not_lemma istype-le int-rdiv_wf exp_wf3 intformeq_wf int_formula_prop_eq_lemma nequal_wf int-rmul_wf exp_wf2 subtract-1-ge-0 istype-nat real_wf int_seg_wf int_seg_properties req_weakening subtype_rel_function bool_wf subtract_wf int_seg_subtype istype-false not-le-2 condition-implies-le add-associates minus-add minus-one-mul add-swap minus-one-mul-top add-mul-special zero-mul add-zero add-commutes le-add-cancel2 subtype_rel_self sq_stable__req ifthenelse_wf lt_int_wf itermSubtract_wf int_term_value_subtract_lemma decidable__lt radd_wf exp_step exp-positive-stronger rless-int nat_plus_properties rmul_preserves_req rless_wf int-to-real_wf req_wf rdiv_wf rmul_wf rminus_wf itermMultiply_wf itermAdd_wf itermMinus_wf rinv_wf2 int_term_value_mul_lemma rneq_functionality rmul-int rneq-int set_subtype_base less_than_wf int_subtype_base subtype_base_sq decidable__equal_int req-iff-rsub-is-0 nat_plus_inc_int_nzero primrec-unroll exp0_lemma req_functionality req_transitivity int-rdiv-one int-rmul-one eqtt_to_assert assert_of_lt_int eqff_to_assert bool_cases_sqequal bool_subtype_base assert-bnot iff_weakening_uiff assert_wf int-rdiv-req rsub_functionality rdiv_functionality int-rmul-req radd_functionality rmul_functionality rmul-rinv3 real_polynomial_null real_term_value_sub_lemma real_term_value_mul_lemma real_term_value_var_lemma real_term_value_add_lemma real_term_value_minus_lemma real_term_value_const_lemma req_inversion rminus_functionality rinv-mul-as-rdiv rinv-of-rmul int-rinv-cancel
Rules used in proof :  sqequalSubstitution sqequalTransitivity computationStep sqequalReflexivity isect_memberFormation_alt introduction cut extract_by_obid sqequalHypSubstitution isectElimination thin hypothesisEquality hypothesis setElimination rename intWeakElimination lambdaFormation_alt natural_numberEquality independent_isectElimination approximateComputation independent_functionElimination dependent_pairFormation_alt lambdaEquality_alt int_eqEquality dependent_functionElimination isect_memberEquality_alt voidElimination sqequalRule independent_pairFormation universeIsType isectIsTypeImplies inhabitedIsType functionIsTypeImplies dependent_set_memberEquality_alt unionElimination productElimination equalityIstype equalityTransitivity equalitySymmetry because_Cache baseClosed sqequalBase intEquality functionIsType applyEquality addEquality minusEquality multiplyEquality productEquality independent_pairEquality productIsType imageMemberEquality imageElimination inrFormation_alt closedConclusion baseApply instantiate cumulativity equalityElimination promote_hyp

Latex:
\mforall{}[a,b:\mBbbR{}].  \mforall{}[n:\mBbbN{}].  \mforall{}[f:\mBbbN{}n  {}\mrightarrow{}  \mBbbB{}].
    (((snd(cantor-interval(a;b;f;n)))  -  fst(cantor-interval(a;b;f;n)))  =  (2\^{}n  *  b  -  a)/3\^{}n)



Date html generated: 2019_10_30-AM-07_37_38
Last ObjectModification: 2018_12_16-PM-04_42_33

Theory : reals


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