182(7.28) ⎧(R i 1u i 1u − i 1 κQk 1x k1 u = Π x,u,Q l′ ,Q l′i 1 x k,... ,Q l′′ x 1 k ′ ···x 1 k,Q l′′κ−1 u i′ 1 ,Rj′ ,Rx j′k,... ,R j′′1⎪⎨⎪⎩,R j′,R j′,... ,R j′,u i′ 1 x k ′ u i′ 1 x k ′ ···x k ′ u i′ 11 1 κ−2(R j u i 1u = Π x,u,Q l′ ,Q l′i 1 x k,... ,Q l′′ x k ′ ···x k,Q l′′1 1 κ−1 u i′ 1 ,Rj′ ,Rx j′k,... ,R j′′1)x k ′1 ···x k ′κ−1,x k ′1 ···x k ′κ−1,,R j′,R j′,... ,R j′, j ≠ iu i′ 1 x k ′ u i′ 1 x k ′ ···x k ′ u i′ 1 ,11 1 κ−2(2R i 2u i 1u − i 2 κQk 1x k1 u = Π x,u,Q l′ ,Q l′i 1 x k,... ,Q l′′ x 1 k ′ ···x 1 k,Q l′′κ−1 u i′ 1 ,Rj′ ,Rx j′k,... ,R′ x j′1k ′ ···x 1 k,′κ−1),R j′,R j′,... ,R j′, iu i′ 1 x k ′ u i′ 1 x k ′ ···x k ′ u i′ 1 ≠ i 2 ,11 1 κ−2(R j u i 1u = Π x,u,Q l′ ,Q l′i 2 x k,... ,Q l′′ x k ′ ···x k,Q l′′1 1 κ−1 u i′ 1 ,Rj′ ,Rx j′k,... ,R′ x j′k ′ ···x k,′1 1 κ−1),R j′,R j′,...,R j′u i′ 1 x k ′ u i′ 1 x k ′ ···x k ′ u i′ 11 1 κ−2Using the equations of (7.28) we already obtained (namely all except thesecond equation), using (7.28) and (7.28), we may simplify these four equations:⎧Π(x, u, J) = R i 1u⎪⎨i 1u , i 1Π(x, u, J) = R j u(7.28)i 1u , j ≠ i i 1 1,Π(x, u, J) = R i 1u⎪⎩i 1u , i i 2 1 ≠ i 2 ,Π(x, u, J) = R j u i 1u , i i 2 1 ≠ i 2 , j ≠ i 1 , j ≠ i 2 .This gives the second equation of (7.28), completing the proof of Lemma 8.1and consequently the proof of Theorem 6.4.REFERENCES[1] BAOUENDI, M.S.; EBENFELT, P.; ROTHSCHILD, L.P.: Real submanifolds in complexspace and their mappings. Princeton Mathematical Series, 47, Princeton UniversityPress Princeton, NJ, 1999, xii+404 pp.[2] BLUMAN, G.W.; KUMEI, S.: Symmetries and differential equations, Springer Verlag,Berlin, 1989.[3] CARTAN, É.: Sur la géométrie pseudo-conforme <strong>de</strong>s hyper<strong>sur</strong>faces <strong>de</strong> l’espace <strong>de</strong><strong>de</strong>ux variab<strong>les</strong> complexes, I, Annali di Mat. 11 (1932), 17–90.[4] CHERN, S.S.; MOSER, J.K.: Real hyper<strong>sur</strong>faces in complex manifolds, Acta Math.133 (1974), no.2, 219–271.), i 1 ≠ i 2 , j ≠ i 2 , j ≠ i 2 .
[5] F. ENGEL; LIE, S.: Theorie <strong>de</strong>r Transformationsgruppen, I, II, II, Teubner, Leipzig,1889, 1891, 1893.[6] FELS, M.: The equivalence problem for systems of second-or<strong>de</strong>r ordinary differentialequations, Proc. London Math. Soc. 71 (1995), 221–240.[7] GAUSSIER, H.; MERKER, J.: A new example of uniformly Levi <strong>de</strong>generate hyper<strong>sur</strong>facein C 3 , Ark. Mat., to appear.[8] GAUSSIER, H.; MERKER, J.: Nonalgebraizable real analytic tubes in C n , Math. Z.,to appear.[9] GAUSSIER, H.; MERKER, J.: Sur l’algébrisabilité locale <strong>de</strong> sous-variétés analytiquesréel<strong>les</strong> génériques <strong>de</strong> C n , C. R. Acad. Sci. Paris Sér. I Math., to appear.[10] GAUSSIER, H.; MERKER, J.: Géométrie <strong>de</strong>s sous-variétés analytiques réel<strong>les</strong> <strong>de</strong> C net symétries <strong>de</strong> <strong>Lie</strong> <strong>de</strong>s équations <strong>aux</strong> dérivées partiel<strong>les</strong>, Bull. Soc. Math. Tunisie, toappear.[11] GONZÁLEZ-GASCÓN, F.; GONZÁLEZ-LÓPEZ, A.: Symmetries of differential equations,IV. J. Math. Phys. 24 (1983), 2006–2021.[12] GONZÁLEZ-LÓPEZ, A.: Symmetries of linear systems of second or<strong>de</strong>r differentialequations, J. Math. Phys. 29 (1988), 1097–1105.[13] IBRAGIMOV, N.H.: Group analysis of ordinary differential equations and the invarianceprinciple in mathematical physics, Russian Math. Surveys 47:4 (1992), 89–156.[14] LIE, S.: Theorie <strong>de</strong>r Transformationsgruppen, Math. Ann. 16 (1880), 441–528.[15] MERKER, J.: Vector field construction of Segre sets, Preprint 1998, augmented in2000. Downloadable at arXiv.org/abs/math.CV/9901010.[16] MERKER, J.: On the partial algebraicity of holomorphic mappings between two realalgebraic sets, Bull. Soc. Math. France 129 (2001), no.3, 547–591.[17] MERKER, J.: On the local geometry of generic submanifolds of C n and the analyticreflection principle, Viniti, to appear.[18] OLVER, P.J.: Applications of <strong>Lie</strong> groups to differential equations. Springer Verlag,Hei<strong>de</strong>lberg, 1986.[19] OLVER, P.J.: Equivalence, Invariance and Symmetries. Cambridge, Cambridge UniversityPress, 1995, xvi+525 pp.[20] POINCARÉ, H.: Les fonctions analytiques <strong>de</strong> <strong>de</strong>ux variab<strong>les</strong> et la représentation conforme,Rend. Circ. Mat. Palermo, II, Ser. 23, 185–220.[21] SEGRE, B.: Intorno al problema di Poincaré <strong>de</strong>lla rappresentazione pseudoconforme,Rend. Acc. Lincei, VI, Ser. 13 (1931), 676–683.[22] SEGRE, B.: Questioni geometriche legate colla teoria <strong>de</strong>lle funzioni di due variabilicomp<strong>les</strong>se, Rendiconti <strong>de</strong>l Seminario di Matematici di Roma, II, Ser. 7 (1932), no. 2,59–107.[23] STORMARK, O.: <strong>Lie</strong>’s structural approach to PDE systems. Encyclopædia of mathematicsand its applications, vol. 80, Cambridge University Press, Cambridge, 2000,xv+572 pp.[24] SUKHOV, A.: Segre varieties and <strong>Lie</strong> symmetries, Math. Z. 238 (2001), no.3, 483–492.[25] SUKHOV, A.: On transformations of analytic CR structures, Pub. Irma, Lille 2001,Vol. 56, no. II.[26] SUKHOV, A.: CR maps and point <strong>Lie</strong> transformations, Michigan Math. J. 50 (2002),369–379.[27] SUSSMANN, H.J.: Orbits of families of vector fields and integrability of distributions,Trans. Amer. Math. Soc. 180 (1973), 171-188.183
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Joël M E R K E RÉcole Normale Sup
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§1. INTRODUCTIONSeveral physically
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e a collection of m analytic second
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7where the indices j, l 1 vary in {
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This phenomenon could be explained
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This yields the prolongation of the
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X(x, y) and Y (x, y) such that it m
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2.23. Compatibility conditions for
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This lemma is left to the reader; a
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simplification nor any reordering:(
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aleza, y por otra, las organizacion
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computational level (differential-g
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For instance, in the case m = 2, by
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in (3.11). The second equation that
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Similarly, the second equation take
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order derivatives of X and of the Y
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Lemma 3.32. The system yxx j = F j
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Lemma 3.45. The following quadratic
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often be denoted by the sign “·
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1Now, taking account of the factor
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conditions, totally equivalent to t
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43remaining terms afterwards:(3.71)
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Here, the sign ≡ precisely means:
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Next, replacing plainly (3.64) in (
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49the order of §3.73. We get:(3.89
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51Multiplying by −2 and reorganiz
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⎧Θ l 1y l 2 = −Ll 1l 1 ,l 1 ,y
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+ 1 ∑4 δj l 1Hl k 2L k k,kk− 2
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+ 1 ∑2 δj l 1Hl k 3M l2 ,kk+ 1 4
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In the hardest techical part of thi
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− 1 3+ 1 3− 1 4+ 1 4∑Hl k 1H
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− 1 3∑kL l 1l1 ,k,x Hk l 1+ 1 3
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Here, the sign ≡ means “modulo
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Thirdly, put j := l 2 in (3.108) wi
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69correct. We get:(4.29)0 =?== −
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Next, apply the operator ∑ k Ll 2
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73Writing term by term the substrac
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of the terms of the subgoal (4.29):
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77+ 1 2∑kH k l 1 ,y l 2 Hl 2k15
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79= − X xx Yx j + Y jm∑+++++l 1
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Our first task is to compute the de
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Replacing this expression of A k in
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85have the continuation(5.17) −y
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87and where thirdly (we are nearly
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89obtain:(5.23)III :=m∑m∑l 1 =1
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[GTW1989] GRISSOM, C.; THOMPSON, G.
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93Nonalgebraizable real analytic tu
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and of CR dimension m = n − d ≥
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coordinates z ′ = 2i ln(z/z p ),
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{x ∈ K n : |x| < ρ} for some ρ
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(2) A K-algebraic inversion mapping
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(1) The complex Lie algebra Hol(M,
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Proposition 3.1. Let t ↦→ G i (
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The first relation gives nothing, s
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with |β∗ k | ≥ 1 and integers
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Clearly, the left hand side is an a
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field X 1 ′ := h ∗ (X 1 ). Taki
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which yields after differentiating
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117Im w∆ n(ρ 4 )∆ n(ρ 1 )∆
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[∂ i,ei H ei (t ′ )] t ′ =He
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p = (w p , z p , ζ p , ξ p ) ∈
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Finite nondegeneracy is interesting
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such that |ω j i ∗ ,β∗ i(t,
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for k even, we have Γ k (z (k) ) =
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that for every local holomorphic se
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- Page 135 and 136: functions w(z)). The coefficients R
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- Page 139 and 140: y k ′ = λk k y k and w ′ = µ
- Page 141 and 142: The last statements of Corollaries
- Page 143 and 144: [Sha2000] SHAFIKOV, R.: Analytic co
- Page 145 and 146: Here x = (x 1 , . . ., x n ) ∈ K
- Page 147 and 148: Consequently, for the case κ = 2,
- Page 149 and 150: are devoted to provide a general on
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- Page 155 and 156: 155namely X ←→ X + X ←→ X .
- Page 157 and 158: In terms of Sussmann’s approach [
- Page 159 and 160: x κ−1 χ κ−1 + O(|x| κ ) + O
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- Page 163 and 164: where the first term I involves onl
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- Page 179 and 180: the values of the partial derivativ
- Page 181: also appears some derivatives Q l
- Page 185 and 186: 185Nonrigid sphericalreal analytic
- Page 187 and 188: origin:{ ( ∣ ∣ )AJ 4 1∣∣∣
- Page 189 and 190: I 2 characterizes equivalence to w
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- Page 199 and 200: We notice passim that S ≡ Q x (no
- Page 201 and 202: for a certain local K-analytic new
- Page 203 and 204: Conversely, if y xx (x) = F ( x, y(
- Page 205 and 206: 205But we may also express the dual
- Page 207 and 208: Then thanks to a straightforward ap
- Page 209 and 210: and we then expand carefully the re
- Page 211 and 212: explicit computation, so let us rew
- Page 213 and 214: 213+T ah3Q 2 a Q b∆(aa|b)∆(b|bb
- Page 215 and 216: 215Vanishing Hachtroudi curvaturean
- Page 217 and 218: to fix the ideas, it will be assume
- Page 219 and 220: then by replacing the(so obtained)v
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- Page 229 and 230: ∂Here, the coefficients of the2 T
- Page 231 and 232: 231for (7.28):( )∂□ ·∂a □
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233Lie symmetriesof partial differe
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Differentiating the first equation
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Example 1.21. (Continued) With n =
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defined by the graphed equations:((
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for some two local analytic maps Π
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Proof. Let l = l ( x i , y j , yβ(
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complementary views on the same obj
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Classification problem 3.11. Classi
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Definition 4.10. L is an infinitesi
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Convention 5.2. The letters R will
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Assuming that dimSYM(E 1 ) = 8, tak
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Restarting from §4.1, let ϕ a Lie
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Here, R j l 1 ,kare universal polyn
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Lemma 6.34. Let M be a submanifold
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where the expressions D β,β1 are
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Then the sum L + L is tangent to M
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Lemma 7.11. ([CM1974, BER1999, Me20
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where(7.33) ∆ := ∑1kn∂ 2∂x
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with r, s being unspecified functio
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and moreover, all other, higher ord
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To conclude, we replace X xx so obt
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Definition 8.43. A real analytic hy
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Lemma 8.59. The function b depends
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where the letter r denotes an unspe
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(8.80) ⎧Y 1,1,1 = Y x 1 x 1 x 1 +
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(X 1 , X 2 , Y , Xy 1,X 2x, Y 2 x 1
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espect to x 1 and (8.96) 2 with res
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For the two unknowns Xyy 1 and X 2x
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Redeveloping the determinant, the v
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291are obtained by equating to zero
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Let (z 0 , c 0 ) = (x 0 , y 0 , a 0
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we deduce that Γ 5 is submersive (
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11.4. Regularity and jet parametriz
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Cramer’s rule, we get(11.13) ⎧
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in K[a, z] n+m and in K[x, c] p+m .
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of the cancellation properties (11.
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305II: Explicit prolongations of in
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Define then the transformed jet ϕ
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Let λ ∈ N be an arbitrary intege
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311[Ol1986], [BK1989]):(Y(1.31)⎧
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+ [Y y 2 − 2 X xy ] y 1 y 2 + [
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for some nonnegative integers A, B,
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Once the correct theorem is formula
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By the classical formula for the de
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The induction formulas are⎧(3.4)
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We have to compute:( ) ⎛ ⎞∑
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Next, we gather the underlined term
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+ ∑k 1 ,k 2 ,k 3 ,k 4[−δ k 1,k
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Correspondingly, we identify the se
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must be equal to the number of indi
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Y i1 ,i 2 ,i 3 ,i 4written in one o
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335conclusion, we have shown that (
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337Theorem 3.73. For every κ 1 an
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Theorem 3.79. For every integer κ
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+++m∑l 1 ,l 2 =1m∑l 1 ,l 2 ,l 3
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343form:(4.12)κ+1Yκ j = Y jx κ +
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eing related to the number 2 in the
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Appying the chain rule, we may comp
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Secondly:(5.3)Y j i 1 ,i 2= Y jx i
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As explained before the statement o
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g j i 1 ,...,i λand similarly for
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with respect to the variables x i 1
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Assuming F = F(x, y x ) to be indep
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359(III’) ⎧0 = ∑ (δ k 2)j 3H
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Open problem 1.17. For n = 2 establ
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⎧∣ ⎨X 1 xX 1+ y x 1 y x 1 ·1
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eplacing the third column by the se
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⎧ ∣ ∣⎫ ⎨ ∣∣∣∣∣
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e written under the specific form:(
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Indeed, the collection of equations
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3.12. Principal unknowns. As there
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375Sixthly:(3.22) ⎧δ k 1j 1Θ n+
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are a consequence of (I’), (I”)
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379IV: BibliographyREFERENCES[Ar198
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[G1989] GARDNER, R.B.: The method o
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[Me2005a] MERKER, J.: On the local