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Real Algebraic Numbers: Complexity Analysis and Experimentations Ioannis Z. Emiris, Bernard Mourrain, Elias P. Tsigaridas To cite this version: Ioannis Z. Emiris, Bernard Mourrain, Elias P. Tsigaridas. Real Algebraic Numbers: Complexity Analysis and Experimentations. P. Hertling, C. Hoffmann, W. Luther and N. Revol. Reliable Implementations of Real Number Algorithms: Theory and Practice, 2008, Dagsthul, Germany. Springer, 5045, pp.57-82, 2008, Lecture Notes in Computer Science. <inria-00071370> HAL Id: inria-00071370 https://hal.inria.fr/inria-00071370 Submitted on 23 May 2006 HAL is a multi-disciplinary open access archive for the deposit and dissemination of sci- entific research documents, whether they are pub- lished or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L’archive ouverte pluridisciplinaire HAL, est destin´ ee au d´ epˆ ot et ` a la diffusion de documents scientifiques de niveau recherche, publi´ es ou non, ´ emanant des ´ etablissements d’enseignement et de recherche fran¸cais ou ´ etrangers, des laboratoires publics ou priv´ es.

Real Algebraic Numbers: Complexity Analysis and ... · Real Algebraic Numbers: Complexity Analysis and Experimentations Ioannis Z. Emiris, Bernard Mourrain, Elias P. Tsigaridas To

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Page 1: Real Algebraic Numbers: Complexity Analysis and ... · Real Algebraic Numbers: Complexity Analysis and Experimentations Ioannis Z. Emiris, Bernard Mourrain, Elias P. Tsigaridas To

Real Algebraic Numbers: Complexity Analysis and

Experimentations

Ioannis Z. Emiris, Bernard Mourrain, Elias P. Tsigaridas

To cite this version:

Ioannis Z. Emiris, Bernard Mourrain, Elias P. Tsigaridas. Real Algebraic Numbers: ComplexityAnalysis and Experimentations. P. Hertling, C. Hoffmann, W. Luther and N. Revol. ReliableImplementations of Real Number Algorithms: Theory and Practice, 2008, Dagsthul, Germany.Springer, 5045, pp.57-82, 2008, Lecture Notes in Computer Science. <inria-00071370>

HAL Id: inria-00071370

https://hal.inria.fr/inria-00071370

Submitted on 23 May 2006

HAL is a multi-disciplinary open accessarchive for the deposit and dissemination of sci-entific research documents, whether they are pub-lished or not. The documents may come fromteaching and research institutions in France orabroad, or from public or private research centers.

L’archive ouverte pluridisciplinaire HAL, estdestinee au depot et a la diffusion de documentsscientifiques de niveau recherche, publies ou non,emanant des etablissements d’enseignement et derecherche francais ou etrangers, des laboratoirespublics ou prives.

Page 2: Real Algebraic Numbers: Complexity Analysis and ... · Real Algebraic Numbers: Complexity Analysis and Experimentations Ioannis Z. Emiris, Bernard Mourrain, Elias P. Tsigaridas To

ISS

N 0

249-

6399

ISR

N IN

RIA

/RR

--58

97--

FR

+E

NG

ap por t de r ech er ch e

Thème SYM

INSTITUT NATIONAL DE RECHERCHE EN INFORMATIQUE ET EN AUTOMATIQUE

Real Algebraic Numbers: Complexity Analysis andExperimentations

I.Z. Emiris — B. Mourrain — E. Tsigaridas

N° 5897

Avril 2006

Page 3: Real Algebraic Numbers: Complexity Analysis and ... · Real Algebraic Numbers: Complexity Analysis and Experimentations Ioannis Z. Emiris, Bernard Mourrain, Elias P. Tsigaridas To
Page 4: Real Algebraic Numbers: Complexity Analysis and ... · Real Algebraic Numbers: Complexity Analysis and Experimentations Ioannis Z. Emiris, Bernard Mourrain, Elias P. Tsigaridas To

Unité de recherche INRIA Sophia Antipolis2004, route des Lucioles, BP 93, 06902 Sophia Antipolis Cedex (France)

Téléphone : +33 4 92 38 77 77 — Télécopie : +33 4 92 38 77 65

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Page 7: Real Algebraic Numbers: Complexity Analysis and ... · Real Algebraic Numbers: Complexity Analysis and Experimentations Ioannis Z. Emiris, Bernard Mourrain, Elias P. Tsigaridas To

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Page 8: Real Algebraic Numbers: Complexity Analysis and ... · Real Algebraic Numbers: Complexity Analysis and Experimentations Ioannis Z. Emiris, Bernard Mourrain, Elias P. Tsigaridas To

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A = α1, . . . , αkE

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S @k,HEbFSkFkMF¾_5m

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B r SPRS (A, B) r H?qRjRLonE L< <pRE

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rem (Rk−1, Rk) = 0 s MqRwxr|mpuv_5dmkp_Gwdx]_G_Lh AE

B .HqG)jRLonE L<%<pRE Qi0≤i≤k ruwqG

Qi = quo (Ri, Ri+1)E HqG~wdx]r|mou¥_Gmq+rjr|m

(Q0, Q1, . . . , Qk−1, Rk) s

Page 9: Real Algebraic Numbers: Complexity Analysis and ... · Real Algebraic Numbers: Complexity Analysis and Experimentations Ioannis Z. Emiris, Bernard Mourrain, Elias P. Tsigaridas To

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¾_5mMj

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§AXq−2−j

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§Xp+q−2−j , . . . , X, 1

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u=k(p+q−1−2j)×(p+q−1−j)

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M lj

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rtsvx]^`kt'mo[]_l±Fmp[5rtsvx]^`©rt¬

Mj

¶c ÌX , *¹ * Ð , MqG H F P<q%H <pRE Lh

AE

B r HqG:<pRE

StHa(A, B) = (Hp = Hp(A, B), . . . , H0 = Ho(A, B))

uwqGHp = A, Hp−1 = B

E Hj =

∑jl=0 det (M l

j)Xl s MqR <pRE <LhSj FJE jG H F PqHL KERH

(hp = hp(A, B), . . . , h0(A, B)) Y.E '

hp = 1E

hj

H?qR L ERHLhXj

JEHqG jGLonEL

Hj rhL

0 ≤ j ≤ p s qRE hj = 0hL:LW

jHqGE HqG <pRE JU Y!hH JM rLHqGuT ELE PhH JM' s

·³¬StHa(A, B)

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StHa(A, B)JE OB(pq M (pτ)) rL OB(p2qτ) s LLM r L (Hj(A, B)) = O(pτ) s

¾_5mÉmp[]_wxr|mpuv_5dm¾q+rjr|m¾mo[;m5rtzozp_Pk+rtk+mprStHa(A, B)

§;q_StHaQ(A, B) = (Q0, Q1, . . . , Qk−1, Hk)

¶Z []_Bjx]^"q_Gzr|¬85rj_¯'uv_5dmok uv

StHaQ(A, B)uvk O(q)

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LM ER

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StHaQ(A, B) SN n LkjHI s%$ E LHq@H?qRDL j U-lYJH9n

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Ω(p)§|­_^bxkm_Gz¬¹rzp^

Ω(p)^bxs¦mou¥]svu=5;mou¥rkq+_mn­&_5_Gµjx]^bq+_5z)krt¬Tq]u¦m7kuv°5_ O(pτ)

t O(p2τ)§+mp[jxkmo[]_br;_5z)|svsr^`]s¥_5¨lu¦mni

u=k OB(p3M (pτ))

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Page 10: Real Algebraic Numbers: Complexity Analysis and ... · Real Algebraic Numbers: Complexity Analysis and Experimentations Ioannis Z. Emiris, Bernard Mourrain, Elias P. Tsigaridas To

]N^ ÌjÐ Ì MqR 0pR oh jRFHLhA r s s Ared r E LkjHI +hL

StHa(A, A′

) r JEOB(p lg pM (pτ))

L OB(p2τ) r E L (Ared) = O(p + τ) s¾_5m

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t

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i + t br−1i+1 (t), 0 ≤ i ≤ d − r, 0 ≤ r ≤ d.

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b− = (bi0)i=0,...,d

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i )i=0,...,d

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fr

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[(1 − t)a + tb, b]À¶

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d¶7Â]rtz

λ 6= 0, µ ∈ R§Értku=l_5zUmp[]_b¬¹rtsvs¥r;­uv]'^/tk

R2 → R2 !

% ρ : (x, y) 7→ (y, x)§

% Hλ : (x, y) 7→ (λx, y)§H ′

λ : (x, y) 7→ (x, λy)§

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µ : (x, y) 7→ (x, y − µx)¶

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§ρ(p) = xdp(1/x)

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§H ′

λ(p) = p(λ−1x)§Tµ(p) = p(x−µ)

§T ′

µ(p) = (1−µ x)dp( x1−µ x

Page 11: Real Algebraic Numbers: Complexity Analysis and ... · Real Algebraic Numbers: Complexity Analysis and Experimentations Ioannis Z. Emiris, Bernard Mourrain, Elias P. Tsigaridas To

5<JF LFJEVF YFP

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∑di=0 biB

id(x; a, b)

§]­&_>[Öt_

ρ T1 ρ Hb−a T−a(p) =

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i=0

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i

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i.

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id(x; c, d)

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(di

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(di

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iu=k

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b−a

T ′−1

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12

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­u¥mp[u¥dmo_5t_Gzrj_¯'5u¥_Gm)k5¶6 Ð\Ð +*¹+* Ð, __ f H

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2

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i

2i

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[a, a+b2 ]

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Page 12: Real Algebraic Numbers: Complexity Analysis and ... · Real Algebraic Numbers: Complexity Analysis and Experimentations Ioannis Z. Emiris, Bernard Mourrain, Elias P. Tsigaridas To

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Page 13: Real Algebraic Numbers: Complexity Analysis and ... · Real Algebraic Numbers: Complexity Analysis and Experimentations Ioannis Z. Emiris, Bernard Mourrain, Elias P. Tsigaridas To

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β, βu¥mp[_

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d

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Page 14: Real Algebraic Numbers: Complexity Analysis and ... · Real Algebraic Numbers: Complexity Analysis and Experimentations Ioannis Z. Emiris, Bernard Mourrain, Elias P. Tsigaridas To

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I ∈ I !

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|I|≤ |I| lg |b − a| − ∑

I∈I lg |I |≤ |I| lg |b − a| + |I| − ∑

I∈I lg |αI − βI | Prop.QÖ

´&i ¿FtÀ>­&_/[Öt_§ −∑I∈I′ lg |αI − βI | ≤ (d − 1) lg(M(f)) + ( d

2 + |I ′|) lg d − |I ′| lg√

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N < |I| + |I| lg |b − a| − ∑I∈I lg |αI − βI |

≤ d + d(τ + 1) + (d − 1)(2τ + lg(d + 1)) + 2d lg d= O (dτ + d lg d) .

2

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d + 1À§lu¥ OB(δid

2τ)$ t]§GORQF&³¶Lajuv_ ∑m

i=1 δi ≤ dmp[_Br;t_5z)|svsWrkmuvk OB(d3τ)

S E ) 2 - H E·¸mp[]u=kkp_Gmpuvrt¾§l­&_7­u¥svs¾]zor;t_~mp[|m mp[]_7mn­&r/kx]qWluvjuvkpu¥rkrs¥_5z)kL[kªq]u¦mU5rt^`]sv_¨lu¥mni OB(d4τ2)

!]N^ ÌjÐ Ì `_ f H

f ∈ Z[X ] r uTJHq deg(f) = dE L (f) = τ r ELH5E FJon0pR oh s E LUH H?qR=5L LHZLh

fE YHIF JE =H?qRJD NH j JH FZ%FJE H F L CFEGFHIJE WHqGL '

OB(d4τ (τ+d)) s LLM r HqGBE jRLJE HBLhH?qR LUH JEWJE H FM SqRM:JH F#"+LE P W/n O(d τ) s6 оÐx ¢ ·¸®rtz)l_Gz>u=kprts=;mp_ªmo[]_/zp_P|sTzorjr|mok7rt¬ +rtsvij]rt^`u=|s

f§­&_z)knm5rt^`]xlmo_`mp[]_ºkowdx|zo_"¬¹zp_G_/|zpm

r|¬f¿Ákmp_5 QPÀ¶7Z [uvk>5t«q+_ªlr]_buv OB(d2τ)

tzpu¥mp[]^`_5mpu=rt+_5z);mou¥rkUtµijuv_5s=]k>º+rtsvij]rt^`u=|sfred

§­[]u=)[5rj_¯'uv_5dmoktzp_7rt¬8kpu¥°G_>q+rtxl_Gqji O(d + τ)

¿Ákp_5_Bkp_G.mou¥rl¶ QGÀ.¶Z []uvkkmp_Guvk ]rtm]_G5_Gkokptzpi/uvadmox]zp^Ò k^`_mo[]rlɶ

Z []_G¾§uv»mp[]_ºadmox]zo^Ò kB^`_mo[]rlɧ8­_`[Ö_"morµr^ªxlmp_`mo[]_ºadmpxzp^ª±¸²U|quv)[dmk_Pwdx]_55_`r|¬f§­[]u=)[

rdknm)k OB(d3τ)¿ÁZ [¾¶&|À.¶

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mpr»mp[]_´&_5zokmp_Gu¥ qtkpuvkªrt¬[a, b]

¿Á­u¦mo[a = −2τ

§b = 2τ

À.¶½Z [uvk`5t½q+_]rt]_u¥ O(d2)|zou¦mo[]^`_mpu=©rt+_5z);mpuvrtk"tu¥m`zprllx5_Gkªrj_¯'5u¥_Gm)kbrt¬~kpu¥°G_

O(dτ + d2)¶@Z [jxk&mp[]_5rkmr|¬8mp[]u=k&mpz)|k¬¹rtzo^/;mou¥rºu=kqrx]l_P OB(d3(d + τ))

¶·¸qrtmp[5k_§l­_7[Ö_

τ = O(d τ + d2)¿Ákp_5_kp_G.mou¥r]¶ À.¶

Z []_G­&_zox]mp[]_b^`tu¥svrjrtr|¬mo[]_bkpx]q+]u¥ju=kuvrtµts¥rtzou¦mo[]^¶Z []_b5rkmr|¬@/kpx]q+]u¥ju=kuvrtµ|mU/s¥_Gt_Gshuvºmo[]u=kkxq+luvjuvkpuvrtmpzo_5_7u=k u¥ OB(d2(d τ + d2 + h))

¿Ákp_Gmpuvrtl¶ tÀ.¶

Page 15: Real Algebraic Numbers: Complexity Analysis and ... · Real Algebraic Numbers: Complexity Analysis and Experimentations Ioannis Z. Emiris, Bernard Mourrain, Elias P. Tsigaridas To

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O(d τ)¶&Z []_5zo_¬¹rzp_§dmp[]_Br;_5z)|svs+5rt^`]sv_¨lu¦mniºr|¬qrtmp[kxq+luvjuvkpuvrtkrs¥_5z)ku=k OB(d4 τ(τ + d))

¶2

5 ©-`» 8

Z []_&zp_P|sj|svt_Gq]zotuvLjx]^bq+_5z)k5§ÖuF¶ _¶mo[]rkp_&zp_P|sddx^bq+_5z)kmo[;mTko;mpu=k¬¹iU+rtsvij]rt^`u=|sd_Gwdx;mou¥r­u¥mp[ªu¥dmp_Gt_Gzrj_5¯/5u¥_GdmokG§j¬¹rtzo^1ªzp_P|sÉsvrkp_G_5s=l_5r|mp_Pºqji

Ralg = Q¶@Âzpr^1|svsÉuvmo_5_5z rs¥ij]r^`uvtsvk&mo[;m[Ö_

||svt_Gq]zotuvdx^bq+_5zαtkzprjr|mP§tmo[]_7rt]_~­u¦mo[ºmo[]_>^ªuv]uv^bx]^ ]_5tzo_5_~uvk G|svs¥_P <JERJà¶@Z []_>^`u¥u¥^/|s

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α ∈ Ralg

α ∼=

(P (X), I) r uwqG P (X) ∈ Z[X ] W0pR ohSE

P (α) = 0 r I = [a, b] r a, b,∈ QE

PqGEL

LHqGL+LH5JEI s

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f§]­u¦mo[

deg(f) = d| L (f) = τ

§uv OB(d4τ2)|©mo[]__5lru¥dm)kr|¬mp[_

u=krsv|mpuv]"uvdmp_Gzp;|s=k [Ö_>qu¦mUkpu¥°G_ O(dτ)¶

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Q(X) ∈ Z[X ] r uwqG deg(Q) = dE L (Q) = τ r E =S Y+WE W

α ∼= (P, [a, b]) s E?LkjHI sign(Q(α))JE OB(d3τ) s

6 оÐx ¢ ´iªZ [¾¶§sign(Q(α)) = sign(WP,Q[a, b] ·P ′

(α))¶@Z [jxkT­&_]_G_G"mprB+_5zp¬¹rtzo^ mn­&rB_5;ts¥x|mpuvrtk

r|¬StHa(P, Q)

r;t_Gzmo[]__5]ru¥dmok@r|¬mo[]_u=krsv|mpuv]~uvdmp_Gzp;|slrt¬α¶TZ []_rt^`]sv_¨lu¥mnir|¬+_G)["u=k OB(d3τ)¿ÁZ [¶À.§]­[]u=)[uvktsvkprªmp[]_5rt^`]sv_¨lu¥mni'r|¬0mp[]_Br_Gzo|mpuvrt¾¶

2

Ð Ð ' 'Y l Í _ E2LkjG Hu.L E WBJE LUH JE%SJE H FM# j FERHIH LE JEOB(d3τ) s6 оÐx ¢ ¾_5m`mn­r|svt_Gq]z)|u=ºjx]^"q_Gzok

γ1∼= (P1(x), I1)

|γ2

∼= (P2(x), I2)­[]_Gzp_

I1 = [a1, b1]§

I2 = [a2, b2]¶>¾_5m

J = I1 ∩ I2¶ £ []_G

J = ∅ §rzUr]s¥irt_br|¬ γ1|

γ2q+_5svrt]ºmpr

J§+­&_"5t_Gkuvs¥i

rtz)l_Gzmp[]_ª`|svt_5qzotuv7jx]^"q_GzokG¶·³¬γ1, γ2 ∈ J

§]mo[]_5γ1 ≥ γ2 ⇔ P2(γ1) · P

2(γ2) ≥ 0¶ £ _rtqlm)|uvmp[]_

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2(γ2)§xkuv]/¾_G^¶ QGl§lmo[jxk mp[_rt^`]sv_¨lu¥mni'r|¬r^ª|zouvkprt©uvk OB(d3τ)

¶2

[#* 'ÁG ,8ÌjÐ 8W* ,8Ì 8 ' *¹ * Ì -U_mP§A1, . . . , An1

§B1, . . . , Bn2

§C1, . . . , Cn3

∈ Z[X ]§+­u¦mo[µl_5zp_G_

q+rtx]]_Gqjid|rj_5¯/5u¥_Gdmq]u¦m>kuv°5_Bq+rtx]l_Gqji

τ¶ £ _­uvkp[mpr'5rt^`]xlmo_Bmp[]_bdx^bq+_5zrt¬tmp[]_

zo_G|sWzorjr|mokG§γ§lr|¬

Pkx)[©mp[;m

Ai(γ) > 0§Bj(γ) < 0

|Ck(γ) = 0

t1 ≤ i ≤ n1, 1 ≤ j ≤ n2, 1 ≤

k ≤ n3¶@¾_5m

n = n1 + n2 + n3¶

Ð Ð ' 'Y l Í MqR< E2 LFJHq% HqGH9LNM' HqG j LPU LhFJ<NH EL%JE pR JH i $ m JEOB(d4τ maxn, τ) s6 оÐx ¢ Â8uvzokm0­&_5rt^`]xlmo_Lmo[]_&uvkprts=;mou¥]Uu¥dmp_Gzp;tszo_5]zo_Gkp_5dm);mpuvrtBrt¬|svstmo[]_&zp_P|sdzprjr|m)k¾rt¬

Pu¥ OB(d4τ2)¿ÁZ [¶QGtÀ¶Z [_5zo_&tzp_ ;mT^`rkm

d¶TÂ]rz8_Gt_Gzpi7zo_G|sjzorjr|m

γrt¬

P§;¬¹rz_5t_GzpiB+rtsvij]rt^`u=|s

Ai

§Bj

§Ck

­_r^ª±]xlmo_Umo[]_

sign (Ai(γ))§sign (Bj(γ))

|sign (Ck(γ))

¶Lalu¥ºl_mo_5zo^`u¥|mpuvrtrkmok OB(d3τ)¿Á_5^¶ QGÀ

|`u¥/mo[]_­&rtz)knmLGtkp_­&_^bxkm5rt^`]xlmo_nr|¬Wmp[_5^¶TZ [dxkTmp[_Ur;t_Gzots¥s]5rkmLu=k OB(maxnd4τ, d4τ2) ¶

2Z []u=kuv^ªzpr;_GkLmp[]_B¼j]r;­qrx]]kqdiºrt]_7rtz mn­&rª¬Átmprtz)k&u¥mo[]_Bq]u¥mUrt^`]sv_¨lu¥mni'^`rll_5sF¶

Page 16: Real Algebraic Numbers: Complexity Analysis and ... · Real Algebraic Numbers: Complexity Analysis and Experimentations Ioannis Z. Emiris, Bernard Mourrain, Elias P. Tsigaridas To

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Page 17: Real Algebraic Numbers: Complexity Analysis and ... · Real Algebraic Numbers: Complexity Analysis and Experimentations Ioannis Z. Emiris, Bernard Mourrain, Elias P. Tsigaridas To

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Unité de recherche INRIA Sophia Antipolis2004, route des Lucioles - BP 93 - 06902 Sophia Antipolis Cedex (France)

Unité de recherche INRIA Futurs : Parc Club Orsay Université - ZAC des Vignes4, rue Jacques Monod - 91893 ORSAY Cedex (France)

Unité de recherche INRIA Lorraine : LORIA, Technopôle de Nancy-Brabois - Campus scientifique615, rue du Jardin Botanique - BP 101 - 54602 Villers-lès-Nancy Cedex (France)

Unité de recherche INRIA Rennes : IRISA, Campus universitaire de Beaulieu - 35042 Rennes Cedex (France)Unité de recherche INRIA Rhône-Alpes : 655, avenue de l’Europe - 38334 Montbonnot Saint-Ismier (France)

Unité de recherche INRIA Rocquencourt : Domaine de Voluceau - Rocquencourt - BP 105 - 78153 Le Chesnay Cedex (France)

ÉditeurINRIA - Domaine de Voluceau - Rocquencourt, BP 105 - 78153 Le Chesnay Cedex (France)

ISSN 0249-6399