Nuprl Lemma : rsub-approx

[a,b:ℝ]. ∀[n:ℕ+].  ((a b) ((a (4 n)) (4 n)) ÷ 4)


Proof




Definitions occuring in Statement :  rsub: y real: nat_plus: + uall: [x:A]. B[x] apply: a divide: n ÷ m multiply: m subtract: m natural_number: $n sqequal: t
Definitions unfolded in proof :  uall: [x:A]. B[x] member: t ∈ T uimplies: supposing a rsub: y divide: n ÷ m rminus: -(x) subtract: m real: nat_plus: + all: x:A. B[x] decidable: Dec(P) or: P ∨ Q not: ¬A implies:  Q satisfiable_int_formula: satisfiable_int_formula(fmla) exists: x:A. B[x] false: False top: Top and: P ∧ Q prop: int_nzero: -o true: True nequal: a ≠ b ∈  sq_type: SQType(T) guard: {T}
Lemmas referenced :  subtype_base_sq int_subtype_base radd-approx rminus_wf divide_wfa subtract_wf nat_plus_properties decidable__lt full-omega-unsat intformand_wf intformnot_wf intformless_wf itermConstant_wf itermMultiply_wf itermVar_wf istype-int int_formula_prop_and_lemma istype-void int_formula_prop_not_lemma int_formula_prop_less_lemma int_term_value_constant_lemma int_term_value_mul_lemma int_term_value_var_lemma int_formula_prop_wf istype-less_than nequal_wf nat_plus_wf real_wf
Rules used in proof :  sqequalSubstitution sqequalTransitivity computationStep sqequalReflexivity isect_memberFormation_alt introduction cut thin instantiate extract_by_obid sqequalHypSubstitution isectElimination cumulativity intEquality independent_isectElimination hypothesis sqequalRule hypothesisEquality applyEquality setElimination rename dependent_set_memberEquality_alt multiplyEquality natural_numberEquality dependent_functionElimination unionElimination approximateComputation independent_functionElimination dependent_pairFormation_alt lambdaEquality_alt int_eqEquality isect_memberEquality_alt voidElimination independent_pairFormation universeIsType because_Cache lambdaFormation_alt equalityTransitivity equalitySymmetry equalityIstype baseClosed sqequalBase axiomSqEquality isectIsTypeImplies inhabitedIsType

Latex:
\mforall{}[a,b:\mBbbR{}].  \mforall{}[n:\mBbbN{}\msupplus{}].    ((a  -  b)  n  \msim{}  ((a  (4  *  n))  -  b  (4  *  n))  \mdiv{}  4)



Date html generated: 2019_10_16-PM-03_07_46
Last ObjectModification: 2019_05_23-PM-05_22_49

Theory : reals


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