Nuprl Lemma : atan-small_wf
∀[x:ℝ]. atan-small(x) ∈ {y:ℝ| arctangent(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: x = y
, 
int-to-real: r(n)
, 
real: ℝ
, 
uimplies: b 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: b supposing a
, 
atan-small: atan-small(x)
, 
rneq: x ≠ y
, 
guard: {T}
, 
or: P ∨ Q
, 
all: ∀x:A. B[x]
, 
iff: P 
⇐⇒ Q
, 
and: P ∧ Q
, 
rev_implies: P 
⇐ Q
, 
implies: P 
⇒ Q
, 
less_than: a < b
, 
squash: ↓T
, 
less_than': less_than'(a;b)
, 
true: True
, 
prop: ℙ
, 
subtype_rel: A ⊆r 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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