Nuprl Lemma : rcos-positive-before-half-pi
∀x:{x:ℝ| x ∈ [r0, π/2)} . (r0 < rcos(x))
Proof
Definitions occuring in Statement : 
halfpi: π/2
, 
rcos: rcos(x)
, 
rcoint: [l, u)
, 
i-member: r ∈ I
, 
rless: x < y
, 
int-to-real: r(n)
, 
real: ℝ
, 
all: ∀x:A. B[x]
, 
set: {x:A| B[x]} 
, 
natural_number: $n
Definitions unfolded in proof : 
member: t ∈ T
, 
uall: ∀[x:A]. B[x]
, 
all: ∀x:A. B[x]
, 
sq_stable: SqStable(P)
, 
implies: P 
⇒ Q
, 
top: Top
, 
and: P ∧ Q
, 
exists: ∃x:A. B[x]
, 
squash: ↓T
, 
prop: ℙ
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
guard: {T}
, 
uimplies: b supposing a
, 
iff: P 
⇐⇒ Q
, 
rev_implies: P 
⇐ Q
, 
itermConstant: "const"
, 
req_int_terms: t1 ≡ t2
, 
false: False
, 
not: ¬A
, 
uiff: uiff(P;Q)
, 
converges-to: lim n→∞.x[n] = y
, 
sq_exists: ∃x:{A| B[x]}
, 
nat: ℕ
, 
nat_plus: ℕ+
, 
rneq: x ≠ y
, 
or: P ∨ Q
, 
rless: x < y
, 
ge: i ≥ j 
, 
decidable: Dec(P)
, 
satisfiable_int_formula: satisfiable_int_formula(fmla)
, 
rleq: x ≤ y
, 
rnonneg: rnonneg(x)
, 
le: A ≤ B
, 
subtype_rel: A ⊆r B
, 
real: ℝ
, 
rev_uimplies: rev_uimplies(P;Q)
, 
rge: x ≥ y
Lemmas referenced : 
rcos-seq-converges-to-half-pi, 
rcos-seq_wf, 
nat_wf, 
half-pi_wf, 
halfpi_wf, 
sq_stable__rless, 
int-to-real_wf, 
rcos_wf, 
member_rcoint_lemma, 
rcos-seq-positive, 
set_wf, 
real_wf, 
i-member_wf, 
rcoint_wf, 
member_rccint_lemma, 
rleq_wf, 
converges-to_functionality, 
req_weakening, 
req_inversion, 
halfpi-half-pi, 
radd-preserves-rless, 
rsub_wf, 
rless_functionality, 
radd_wf, 
real_term_polynomial, 
itermSubtract_wf, 
itermAdd_wf, 
itermVar_wf, 
itermConstant_wf, 
real_term_value_const_lemma, 
real_term_value_sub_lemma, 
real_term_value_add_lemma, 
real_term_value_var_lemma, 
req-iff-rsub-is-0, 
small-reciprocal-real, 
rless_wf, 
sq_stable__all, 
le_wf, 
rabs_wf, 
rdiv_wf, 
rless-int, 
nat_properties, 
nat_plus_properties, 
decidable__lt, 
satisfiable-full-omega-tt, 
intformand_wf, 
intformnot_wf, 
intformless_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_wf, 
sq_stable__rleq, 
less_than'_wf, 
nat_plus_wf, 
squash_wf, 
sq_stable__less_than, 
decidable__le, 
intformle_wf, 
int_formula_prop_le_lemma, 
rabs-difference-bound-rleq, 
rleq_functionality_wrt_implies, 
rleq_weakening_equal, 
rleq_weakening, 
rsub_functionality_wrt_rleq, 
rleq_weakening_rless
Rules used in proof : 
cut, 
introduction, 
extract_by_obid, 
hypothesis, 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaEquality, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
hypothesisEquality, 
because_Cache, 
lambdaFormation, 
setElimination, 
rename, 
dependent_functionElimination, 
natural_numberEquality, 
independent_functionElimination, 
isect_memberEquality, 
voidElimination, 
voidEquality, 
productElimination, 
sqequalRule, 
imageMemberEquality, 
baseClosed, 
imageElimination, 
dependent_set_memberEquality, 
independent_pairFormation, 
productEquality, 
independent_isectElimination, 
computeAll, 
int_eqEquality, 
intEquality, 
functionEquality, 
inrFormation, 
unionElimination, 
dependent_pairFormation, 
independent_pairEquality, 
applyEquality, 
minusEquality, 
axiomEquality, 
equalityTransitivity, 
equalitySymmetry, 
addEquality
Latex:
\mforall{}x:\{x:\mBbbR{}|  x  \mmember{}  [r0,  \mpi{}/2)\}  .  (r0  <  rcos(x))
Date html generated:
2017_10_04-PM-10_25_19
Last ObjectModification:
2017_07_28-AM-08_49_05
Theory : reals_2
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