Nuprl Lemma : log-by-IVT
∀a:{a:ℝ| r0 < a} . ∃x:ℝ. (x = rlog(a))
Proof
Definitions occuring in Statement : 
rlog: rlog(x)
, 
rless: x < y
, 
req: x = y
, 
int-to-real: r(n)
, 
real: ℝ
, 
all: ∀x:A. B[x]
, 
exists: ∃x:A. B[x]
, 
set: {x:A| B[x]} 
, 
natural_number: $n
Definitions unfolded in proof : 
so_apply: x[s]
, 
true: True
, 
less_than': less_than'(a;b)
, 
squash: ↓T
, 
less_than: a < b
, 
implies: P 
⇒ Q
, 
rev_implies: P 
⇐ Q
, 
and: P ∧ Q
, 
iff: P 
⇐⇒ Q
, 
or: P ∨ Q
, 
guard: {T}
, 
rneq: x ≠ y
, 
uimplies: b supposing a
, 
so_lambda: λ2x.t[x]
, 
uall: ∀[x:A]. B[x]
, 
prop: ℙ
, 
member: t ∈ T
, 
all: ∀x:A. B[x]
, 
sq_stable: SqStable(P)
, 
exists: ∃x:A. B[x]
, 
nat: ℕ
, 
rless: x < y
, 
sq_exists: ∃x:A [B[x]]
, 
nat_plus: ℕ+
, 
ge: i ≥ j 
, 
decidable: Dec(P)
, 
not: ¬A
, 
satisfiable_int_formula: satisfiable_int_formula(fmla)
, 
false: False
, 
top: Top
, 
rfun: I ⟶ℝ
, 
subtype_rel: A ⊆r B
, 
r-ap: f(x)
, 
rge: x ≥ y
, 
rgt: x > y
, 
uiff: uiff(P;Q)
, 
rev_uimplies: rev_uimplies(P;Q)
, 
real: ℝ
, 
rdiv: (x/y)
, 
rmul: a * b
, 
int-to-real: r(n)
, 
rinv: rinv(x)
, 
mu-ge: mu-ge(f;n)
, 
ifthenelse: if b then t else f fi 
, 
lt_int: i <z j
, 
absval: |i|
, 
bfalse: ff
, 
btrue: tt
, 
eq_int: (i =z j)
, 
accelerate: accelerate(k;f)
, 
imax: imax(a;b)
, 
reg-seq-inv: reg-seq-inv(x)
, 
reg-seq-adjust: reg-seq-adjust(n;x)
, 
le_int: i ≤z j
, 
bnot: ¬bb
, 
reg-seq-mul: reg-seq-mul(x;y)
, 
le: A ≤ B
, 
rfun-eq: rfun-eq(I;f;g)
, 
ifun: ifun(f;I)
, 
real-fun: real-fun(f;a;b)
, 
locally-non-constant: locally-non-constant(f;a;b;c)
, 
strictly-increasing-on-interval: f[x] strictly-increasing for x ∈ I
, 
cand: A c∧ B
Lemmas referenced : 
rless-int, 
int-to-real_wf, 
rdiv_wf, 
rless_wf, 
real_wf, 
set_wf, 
sq_stable__rless, 
r-archimedean, 
IVT-locally-non-constant, 
nat_properties, 
nat_plus_properties, 
decidable__lt, 
full-omega-unsat, 
intformand_wf, 
intformnot_wf, 
intformless_wf, 
itermConstant_wf, 
itermVar_wf, 
intformle_wf, 
istype-int, 
int_formula_prop_and_lemma, 
istype-void, 
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_exp_wf, 
i-member_wf, 
rccint_wf, 
req_wf, 
member_rccint_lemma, 
rless-int-fractions2, 
istype-less_than, 
rless_functionality_wrt_implies, 
rleq_weakening_equal, 
rleq_weakening_rless, 
req_functionality, 
rexp_wf, 
real_exp-req, 
rexp_functionality, 
req_weakening, 
rleq_functionality, 
rless_transitivity2, 
radd_wf, 
rless_transitivity1, 
trivial-rleq-radd, 
rleq-int, 
istype-false, 
rleq_functionality_wrt_implies, 
rleq_weakening, 
req_inversion, 
rexp-of-nonneg-stronger, 
derivative-implies-strictly-increasing-simple, 
derivative_functionality_wrt_subinterval, 
riiint_wf, 
subinterval-riiint, 
derivative-rexp, 
derivative_functionality, 
left_endpoint_rccint_lemma, 
right_endpoint_rccint_lemma, 
rleq_wf, 
rexp-positive, 
rless_functionality, 
rless-cases, 
rneq_wf, 
rneq_functionality, 
sq_stable__req, 
rlog_wf, 
uiff_transitivity, 
rlog_functionality, 
req_transitivity, 
rlog-rexp, 
less_than_wf, 
rless-int-fractions3, 
rmul-rdiv-cancel2, 
rmul_wf, 
rmul_preserves_rless, 
rmul_comm, 
rmul-int-rdiv, 
rminus_wf, 
rlog-inv, 
rmul-zero-both, 
rminus-rminus, 
rminus_functionality
Rules used in proof : 
cut, 
baseClosed, 
hypothesisEquality, 
imageMemberEquality, 
independent_pairFormation, 
independent_functionElimination, 
productElimination, 
because_Cache, 
dependent_functionElimination, 
inrFormation, 
independent_isectElimination, 
natural_numberEquality, 
lambdaEquality, 
sqequalRule, 
hypothesis, 
thin, 
isectElimination, 
sqequalHypSubstitution, 
extract_by_obid, 
introduction, 
lambdaFormation, 
sqequalReflexivity, 
computationStep, 
sqequalTransitivity, 
sqequalSubstitution, 
setElimination, 
rename, 
imageElimination, 
minusEquality, 
unionElimination, 
approximateComputation, 
dependent_pairFormation_alt, 
lambdaEquality_alt, 
int_eqEquality, 
isect_memberEquality_alt, 
voidElimination, 
universeIsType, 
dependent_set_memberEquality_alt, 
applyEquality, 
inhabitedIsType, 
equalityTransitivity, 
equalitySymmetry, 
setIsType, 
lambdaFormation_alt, 
closedConclusion, 
inrFormation_alt, 
dependent_set_memberFormation_alt, 
addEquality, 
computeAll, 
productIsType, 
promote_hyp, 
inlFormation_alt, 
multiplyEquality, 
dependent_set_memberEquality, 
dependent_pairFormation, 
addLevel
Latex:
\mforall{}a:\{a:\mBbbR{}|  r0  <  a\}  .  \mexists{}x:\mBbbR{}.  (x  =  rlog(a))
Date html generated:
2019_10_31-AM-06_10_15
Last ObjectModification:
2019_02_04-PM-11_58_53
Theory : reals_2
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