Nuprl Lemma : reduce-halfpi_wf
∀[x:ℝ]. (reduce-halfpi(x) ∈ {n:ℤ| |x - r(n) * π/2| ≤ r(2)} )
Proof
Definitions occuring in Statement : 
reduce-halfpi: reduce-halfpi(x)
, 
halfpi: π/2
, 
rleq: x ≤ y
, 
rabs: |x|
, 
rsub: x - y
, 
rmul: a * b
, 
int-to-real: r(n)
, 
real: ℝ
, 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
set: {x:A| B[x]} 
, 
natural_number: $n
, 
int: ℤ
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
reduce-halfpi: reduce-halfpi(x)
, 
nat_plus: ℕ+
, 
less_than: a < b
, 
squash: ↓T
, 
less_than': less_than'(a;b)
, 
true: True
, 
and: P ∧ Q
, 
subtype_rel: A ⊆r B
, 
prop: ℙ
, 
rless: x < y
, 
sq_exists: ∃x:A [B[x]]
, 
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
, 
false: False
, 
real: ℝ
, 
int-to-real: r(n)
, 
int-rmul: k1 * a
, 
MachinPi4: MachinPi4()
, 
rsub: x - y
, 
radd: a + b
, 
accelerate: accelerate(k;f)
, 
reg-seq-list-add: reg-seq-list-add(L)
, 
cbv_list_accum: cbv_list_accum(x,a.f[x; a];y;L)
, 
cons: [a / b]
, 
atan: atan(a;x)
, 
atan_approx: atan_approx(a;x;M)
, 
atan-log: atan-log(a;M)
, 
gen_log_aux: gen_log_aux(p;c;x;i;n;M)
, 
ifthenelse: if b then t else f fi 
, 
le_int: i ≤z j
, 
bnot: ¬bb
, 
lt_int: i <z j
, 
exp: i^n
, 
primrec: primrec(n;b;c)
, 
primtailrec: primtailrec(n;i;b;f)
, 
subtract: n - m
, 
btrue: tt
, 
bfalse: ff
, 
atan-approx: atan-approx(k;x;N)
, 
poly-approx: poly-approx(a;x;k;N)
, 
rmul: a * b
, 
int-rdiv: (a)/k1
, 
imax: imax(a;b)
, 
absval: |i|
, 
reg-seq-mul: reg-seq-mul(x;y)
, 
poly-approx-aux: poly-approx-aux(a;x;xM;M;n;k)
, 
eq_int: (i =z j)
, 
rminus: -(x)
, 
nil: []
, 
it: ⋅
, 
guard: {T}
, 
rdiv: (x/y)
, 
rinv: rinv(x)
, 
mu-ge: mu-ge(f;n)
, 
reg-seq-inv: reg-seq-inv(x)
, 
rneq: x ≠ y
, 
iff: P 
⇐⇒ Q
, 
rev_implies: P 
⇐ Q
, 
uiff: uiff(P;Q)
, 
rev_uimplies: rev_uimplies(P;Q)
Lemmas referenced : 
reduce-real_wf, 
istype-less_than, 
real_wf, 
int-rmul_wf, 
MachinPi4_wf, 
rless_wf, 
int-to-real_wf, 
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, 
rleq_wf, 
rabs_wf, 
rsub_wf, 
rmul_wf, 
halfpi_wf, 
radd_wf, 
rdiv_wf, 
rless-int, 
rless_transitivity2, 
rleq_weakening_rless, 
rleq_functionality, 
rabs_functionality, 
rsub_functionality, 
req_weakening, 
rmul_functionality, 
req_inversion, 
2-MachinPi4
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation_alt, 
introduction, 
cut, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
dependent_set_memberEquality_alt, 
closedConclusion, 
natural_numberEquality, 
sqequalRule, 
independent_pairFormation, 
imageMemberEquality, 
hypothesisEquality, 
baseClosed, 
hypothesis, 
applyEquality, 
axiomEquality, 
equalityTransitivity, 
equalitySymmetry, 
universeIsType, 
lambdaEquality_alt, 
setElimination, 
rename, 
inhabitedIsType, 
dependent_set_memberFormation_alt, 
dependent_functionElimination, 
unionElimination, 
independent_isectElimination, 
approximateComputation, 
independent_functionElimination, 
dependent_pairFormation_alt, 
isect_memberEquality_alt, 
voidElimination, 
addEquality, 
applyLambdaEquality, 
imageElimination, 
because_Cache, 
inrFormation_alt, 
productElimination
Latex:
\mforall{}[x:\mBbbR{}].  (reduce-halfpi(x)  \mmember{}  \{n:\mBbbZ{}|  |x  -  r(n)  *  \mpi{}/2|  \mleq{}  r(2)\}  )
Date html generated:
2019_10_31-AM-06_06_59
Last ObjectModification:
2019_02_03-PM-04_44_49
Theory : reals_2
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