Nuprl Lemma : arccos_wf
∀[a:{a:ℝ| a ∈ [r(-1), r1]} ]. (arccos(a) ∈ {x:ℝ| (x ∈ [r0, π]) ∧ (rcos(x) = a)} )
Proof
Definitions occuring in Statement : 
arccos: arccos(x)
, 
pi: π
, 
rcos: rcos(x)
, 
rccint: [l, u]
, 
i-member: r ∈ I
, 
req: x = y
, 
int-to-real: r(n)
, 
real: ℝ
, 
uall: ∀[x:A]. B[x]
, 
and: P ∧ Q
, 
member: t ∈ T
, 
set: {x:A| B[x]} 
, 
minus: -n
, 
natural_number: $n
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
squash: ↓T
, 
all: ∀x:A. B[x]
, 
top: Top
, 
arccos: arccos(x)
, 
and: P ∧ Q
, 
pi: π
, 
prop: ℙ
, 
cand: A c∧ B
, 
uimplies: b supposing a
, 
uiff: uiff(P;Q)
, 
req_int_terms: t1 ≡ t2
, 
false: False
, 
implies: P 
⇒ Q
, 
not: ¬A
, 
rev_uimplies: rev_uimplies(P;Q)
, 
subtype_rel: A ⊆r B
Lemmas referenced : 
arcsin_wf, 
member_rccint_lemma, 
istype-void, 
rsub_wf, 
halfpi_wf, 
i-member_wf, 
rccint_wf, 
int-to-real_wf, 
rleq-implies-rleq, 
rleq_wf, 
int-rmul_wf, 
req_wf, 
rcos_wf, 
real_wf, 
itermSubtract_wf, 
itermVar_wf, 
itermConstant_wf, 
req-iff-rsub-is-0, 
rmul_wf, 
rminus_wf, 
itermMinus_wf, 
itermMultiply_wf, 
real_polynomial_null, 
istype-int, 
real_term_value_sub_lemma, 
real_term_value_var_lemma, 
real_term_value_const_lemma, 
rleq_functionality, 
req_weakening, 
int-rmul-req, 
real_term_value_minus_lemma, 
real_term_value_mul_lemma, 
radd_wf, 
itermAdd_wf, 
rsin_wf, 
rminus-rminus, 
req_functionality, 
radd_functionality, 
arcsin-rminus, 
real_term_value_add_lemma, 
uiff_transitivity, 
rcos_functionality, 
rcos-shift-half-pi, 
rminus_functionality, 
rsin-arcsin
Rules used in proof : 
cut, 
introduction, 
extract_by_obid, 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation_alt, 
hypothesis, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
hypothesisEquality, 
applyLambdaEquality, 
setElimination, 
rename, 
sqequalRule, 
imageMemberEquality, 
baseClosed, 
imageElimination, 
dependent_functionElimination, 
isect_memberEquality_alt, 
voidElimination, 
productElimination, 
dependent_set_memberEquality_alt, 
universeIsType, 
minusEquality, 
natural_numberEquality, 
equalityTransitivity, 
equalitySymmetry, 
because_Cache, 
independent_isectElimination, 
independent_pairFormation, 
productIsType, 
setIsType, 
approximateComputation, 
lambdaEquality_alt, 
int_eqEquality, 
applyEquality, 
inhabitedIsType, 
independent_functionElimination
Latex:
\mforall{}[a:\{a:\mBbbR{}|  a  \mmember{}  [r(-1),  r1]\}  ].  (arccos(a)  \mmember{}  \{x:\mBbbR{}|  (x  \mmember{}  [r0,  \mpi{}])  \mwedge{}  (rcos(x)  =  a)\}  )
Date html generated:
2019_10_31-AM-06_16_03
Last ObjectModification:
2019_05_23-AM-11_31_21
Theory : reals_2
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