Nuprl Lemma : rcos-positive
∀x:{x:ℝ| x ∈ (-(π/2), π/2)} . (r0 < rcos(x))
Proof
Definitions occuring in Statement : 
halfpi: π/2
, 
rcos: rcos(x)
, 
rooint: (l, u)
, 
i-member: r ∈ I
, 
rless: x < y
, 
rminus: -(x)
, 
int-to-real: r(n)
, 
real: ℝ
, 
all: ∀x:A. B[x]
, 
set: {x:A| B[x]} 
, 
natural_number: $n
Definitions unfolded in proof : 
all: ∀x:A. B[x]
, 
member: t ∈ T
, 
uall: ∀[x:A]. B[x]
, 
uimplies: b supposing a
, 
rneq: x ≠ y
, 
guard: {T}
, 
or: P ∨ Q
, 
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
, 
nat_plus: ℕ+
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
sq_stable: SqStable(P)
, 
cand: A c∧ B
, 
top: Top
, 
rsub: x - y
, 
rev_uimplies: rev_uimplies(P;Q)
, 
uiff: uiff(P;Q)
, 
rge: x ≥ y
, 
subtype_rel: A ⊆r B
, 
itermConstant: "const"
, 
req_int_terms: t1 ≡ t2
, 
false: False
, 
not: ¬A
Lemmas referenced : 
rless-cases, 
int-to-real_wf, 
rdiv_wf, 
rless-int, 
rless_wf, 
rless-int-fractions2, 
less_than_wf, 
set_wf, 
real_wf, 
i-member_wf, 
rooint_wf, 
rminus_wf, 
halfpi_wf, 
rleq_wf, 
sq_stable__rless, 
member_rooint_lemma, 
rleq_weakening_rless, 
member_rcoint_lemma, 
rcos-positive-before-half-pi, 
rless-int-fractions3, 
rminus-zero, 
radd_functionality, 
radd_comm, 
req_weakening, 
radd-zero-both, 
rabs_functionality, 
rless_functionality, 
radd_wf, 
rabs_wf, 
rabs-rless-iff, 
rminus-int, 
true_wf, 
squash_wf, 
rmul-rdiv-cancel, 
uiff_transitivity2, 
rmul_comm, 
rminus_functionality, 
rmul_over_rminus, 
rmul-rdiv-cancel2, 
req_functionality, 
uiff_transitivity, 
rmul_wf, 
req_wf, 
rmul_preserves_req, 
rleq_weakening, 
rless_transitivity2, 
rabs-difference-rcos-rleq, 
rcos0, 
rsub_functionality, 
rleq_functionality, 
rleq_weakening_equal, 
rleq_functionality_wrt_implies, 
rcos_wf, 
rsub_wf, 
rabs-difference-bound-rleq, 
rless_functionality_wrt_implies, 
rmul-int, 
rmul-distrib, 
req_transitivity, 
rmul-one-both, 
radd-int, 
iff_weakening_equal, 
iff_transitivity, 
rmul_preserves_rless, 
rminus_functionality_wrt_rleq, 
real_term_polynomial, 
itermSubtract_wf, 
itermConstant_wf, 
itermMinus_wf, 
real_term_value_const_lemma, 
real_term_value_sub_lemma, 
real_term_value_minus_lemma, 
req-iff-rsub-is-0, 
rless-implies-rless, 
itermVar_wf, 
real_term_value_var_lemma, 
req_inversion, 
rcos-rminus
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation, 
cut, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
dependent_functionElimination, 
thin, 
isectElimination, 
natural_numberEquality, 
hypothesis, 
independent_isectElimination, 
sqequalRule, 
inrFormation, 
because_Cache, 
productElimination, 
independent_functionElimination, 
independent_pairFormation, 
imageMemberEquality, 
hypothesisEquality, 
baseClosed, 
dependent_set_memberEquality, 
multiplyEquality, 
setElimination, 
rename, 
unionElimination, 
lambdaEquality, 
productEquality, 
imageElimination, 
voidEquality, 
voidElimination, 
isect_memberEquality, 
minusEquality, 
levelHypothesis, 
addLevel, 
equalitySymmetry, 
equalityTransitivity, 
applyEquality, 
universeEquality, 
addEquality, 
computeAll, 
intEquality, 
int_eqEquality
Latex:
\mforall{}x:\{x:\mBbbR{}|  x  \mmember{}  (-(\mpi{}/2),  \mpi{}/2)\}  .  (r0  <  rcos(x))
Date html generated:
2017_10_04-PM-10_25_39
Last ObjectModification:
2017_07_28-AM-08_49_28
Theory : reals_2
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