Nuprl Lemma : atan-small_wf

[x:ℝ]. atan-small(x) ∈ {y:ℝarctangent(x) y}  supposing |x| ≤ (r1/r(2))


Proof




Definitions occuring in Statement :  atan-small: atan-small(x) arctangent: arctangent(x) rdiv: (x/y) rleq: x ≤ y rabs: |x| req: y int-to-real: r(n) real: uimplies: supposing a uall: [x:A]. B[x] member: t ∈ T set: {x:A| B[x]}  natural_number: $n
Definitions unfolded in proof :  uall: [x:A]. B[x] member: t ∈ T uimplies: supposing a atan-small: atan-small(x) rneq: x ≠ y guard: {T} or: P ∨ Q all: x:A. B[x] iff: ⇐⇒ Q and: P ∧ Q rev_implies:  Q implies:  Q less_than: a < b squash: T less_than': less_than'(a;b) true: True prop: subtype_rel: A ⊆B int_upper: {i...} decidable: Dec(P) not: ¬A satisfiable_int_formula: satisfiable_int_formula(fmla) exists: x:A. B[x] false: False top: Top so_lambda: λ2x.t[x] so_apply: x[s] sq_stable: SqStable(P)
Lemmas referenced :  atan_wf atan-size-bound_wf rleq_wf rabs_wf rdiv_wf rless-int rless_wf int-to-real_wf int_upper_properties decidable__lt full-omega-unsat intformand_wf intformnot_wf intformless_wf itermConstant_wf itermVar_wf intformle_wf int_formula_prop_and_lemma int_formula_prop_not_lemma int_formula_prop_less_lemma int_term_value_constant_lemma int_term_value_var_lemma int_formula_prop_le_lemma int_formula_prop_wf real_wf set_wf int_upper_wf sq_stable__rleq equal_wf
Rules used in proof :  sqequalSubstitution sqequalTransitivity computationStep sqequalReflexivity isect_memberFormation introduction cut sqequalRule extract_by_obid sqequalHypSubstitution isectElimination thin dependent_set_memberEquality hypothesisEquality hypothesis because_Cache independent_isectElimination inrFormation dependent_functionElimination productElimination independent_functionElimination independent_pairFormation natural_numberEquality imageMemberEquality baseClosed applyEquality lambdaEquality setElimination rename setEquality unionElimination approximateComputation dependent_pairFormation int_eqEquality intEquality isect_memberEquality voidElimination voidEquality axiomEquality equalityTransitivity equalitySymmetry lambdaFormation imageElimination

Latex:
\mforall{}[x:\mBbbR{}].  atan-small(x)  \mmember{}  \{y:\mBbbR{}|  arctangent(x)  =  y\}    supposing  |x|  \mleq{}  (r1/r(2))



Date html generated: 2018_05_22-PM-03_06_49
Last ObjectModification: 2017_10_26-PM-10_45_32

Theory : reals_2


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