Nuprl Lemma : cheap-real-upper-bound

∀[x:ℝ]. (x ≤ r((((x 1) + 1) ÷ 2) + 1))


Proof




Definitions occuring in Statement :  rleq: x ≤ y,  int-to-real: r(n),  real: ℝ,  uall: ∀[x:A]. B[x],  apply: f a,  divide: n ÷ m,  add: n + m,  natural_number: $n
Definitions unfolded in proof :  uall: ∀[x:A]. B[x],  member: t ∈ T,  nat_plus: ℕ+,  all: ∀x:A. B[x],  decidable: Dec(P),  or: P ∨ Q,  uimplies: b supposing a,  not: ¬A,  implies: P ⇒ Q,  satisfiable_int_formula: satisfiable_int_formula(fmla),  exists: ∃x:A. B[x],  top: Top,  prop: ℙ,  false: False
Lemmas referenced :  real-upper-bound,  decidable__lt,  full-omega-unsat,  intformnot_wf,  intformless_wf,  itermConstant_wf,  istype-int,  int_formula_prop_not_lemma,  istype-void,  int_formula_prop_less_lemma,  int_term_value_constant_lemma,  int_formula_prop_wf,  istype-less_than,  mul-commutes,  real_wf
Rules used in proof :  cut,  introduction,  extract_by_obid,  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  isect_memberFormation_alt,  hypothesis,  sqequalHypSubstitution,  isectElimination,  thin,  hypothesisEquality,  dependent_set_memberEquality_alt,  natural_numberEquality,  dependent_functionElimination,  unionElimination,  independent_isectElimination,  approximateComputation,  independent_functionElimination,  dependent_pairFormation_alt,  lambdaEquality_alt,  isect_memberEquality_alt,  voidElimination,  sqequalRule,  universeIsType

Latex:
\mforall{}[x:\mBbbR{}].  (x  \mleq{}  r((((x  1)  +  1)  \mdiv{}  2)  +  1))



Date html generated: 2019_10_31-AM-06_10_43
Last ObjectModification: 2019_01_30-PM-02_03_09

Theory : reals_2


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