Yu, Mingzhu; Chen, Haibo Multibump positive solutions for Choquard equation with double potentials in \({\mathbb{R}}^3\). (English) Zbl 07784866 Math. Methods Appl. Sci. 46, No. 13, 14299-14320 (2023). MSC: 35J61 35A01 PDFBibTeX XMLCite \textit{M. Yu} and \textit{H. Chen}, Math. Methods Appl. Sci. 46, No. 13, 14299--14320 (2023; Zbl 07784866) Full Text: DOI
Chen, Chao-Nien; Séré, Éric Multiple front standing waves in the FitzHugh-Nagumo equations. (English) Zbl 1490.34050 J. Differ. Equations 302, 895-925 (2021). Reviewer: Abderrazek Benhassine (Monastir) MSC: 34C37 35J50 35K57 34C20 PDFBibTeX XMLCite \textit{C.-N. Chen} and \textit{É. Séré}, J. Differ. Equations 302, 895--925 (2021; Zbl 1490.34050) Full Text: DOI arXiv
Montecchiari, Piero; Rabinowitz, Paul H. A nondegeneracy condition for a semilinear elliptic system and the existence of multibump solutions. (English) Zbl 1467.35136 Calc. Var. Partial Differ. Equ. 60, No. 4, Paper No. 122, 49 p. (2021). Reviewer: Marius Ghergu (Dublin) MSC: 35J47 35J61 35A01 35J50 PDFBibTeX XMLCite \textit{P. Montecchiari} and \textit{P. H. Rabinowitz}, Calc. Var. Partial Differ. Equ. 60, No. 4, Paper No. 122, 49 p. (2021; Zbl 1467.35136) Full Text: DOI
Yu, Mingzhu; Chen, Haibo Multibump solutions for nonlinear Schrödinger-Poisson systems. (English) Zbl 1448.35120 Math. Methods Appl. Sci. 43, No. 7, 4518-4529 (2020). MSC: 35J05 35J10 35J47 35J20 PDFBibTeX XMLCite \textit{M. Yu} and \textit{H. Chen}, Math. Methods Appl. Sci. 43, No. 7, 4518--4529 (2020; Zbl 1448.35120) Full Text: DOI
Zhang, Xu Multibump solutions of a class of second-order discrete Hamiltonian systems. (English) Zbl 1334.39025 Appl. Math. Comput. 236, 129-149 (2014). MSC: 39A12 34C37 PDFBibTeX XMLCite \textit{X. Zhang}, Appl. Math. Comput. 236, 129--149 (2014; Zbl 1334.39025) Full Text: DOI arXiv
Ackermann, Nils; Clapp, Mónica; Pacella, Filomena Alternating sign multibump solutions of nonlinear elliptic equations in expanding tubular domains. (English) Zbl 1273.35132 Commun. Partial Differ. Equations 38, No. 4-6, 751-779 (2013). MSC: 35J61 35B40 PDFBibTeX XMLCite \textit{N. Ackermann} et al., Commun. Partial Differ. Equations 38, No. 4--6, 751--779 (2013; Zbl 1273.35132) Full Text: DOI arXiv
Guo, Yuxia; Tang, Zhongwei Multibump bound states for quasilinear Schrödinger systems with critical frequency. (English) Zbl 1266.35057 J. Fixed Point Theory Appl. 12, No. 1-2, 135-174 (2012). MSC: 35J50 35J62 35B33 PDFBibTeX XMLCite \textit{Y. Guo} and \textit{Z. Tang}, J. Fixed Point Theory Appl. 12, No. 1--2, 135--174 (2012; Zbl 1266.35057) Full Text: DOI
Zou, Wenming Some results on variational and topological methods. (English) Zbl 1254.35086 Ji, Lizhen (ed.) et al., Fifth international congress of Chinese mathematicians. Proceedings of the ICCM ’10, Beijing, China, December 17–22, 2010. Part 2. Providence, RI: American Mathematical Society (AMS); Somerville, MA: International Press (ISBN 978-0-8218-7587-2/pbk; 978-0-8218-7555-1/set). AMS/IP Studies in Advanced Mathematics 51, pt.2, 987-999 (2012). Reviewer: Stepan Agop Tersian (Rousse) MSC: 35J60 35J20 PDFBibTeX XMLCite \textit{W. Zou}, AMS/IP Stud. Adv. Math. 51, 987--999 (2012; Zbl 1254.35086)
Liu, Jia-Quan; Wang, Zhi-Qiang; Guo, Yu-Xia Multibump solutions for quasilinear elliptic equations. (English) Zbl 1247.35045 J. Funct. Anal. 262, No. 9, 4040-4102 (2012). Reviewer: Junichi Aramaki (Saitama) MSC: 35J62 35Q55 PDFBibTeX XMLCite \textit{J.-Q. Liu} et al., J. Funct. Anal. 262, No. 9, 4040--4102 (2012; Zbl 1247.35045) Full Text: DOI
Zhou, Zheng Existence of infinitely many solutions for a class of Allen-Cahn equations in \(\mathbb R^2\). (English) Zbl 1216.35057 Osaka J. Math. 48, No. 1, 51-67 (2011). MSC: 35J61 35A15 35B40 35J20 35B06 37K05 37K10 PDFBibTeX XMLCite \textit{Z. Zhou}, Osaka J. Math. 48, No. 1, 51--67 (2011; Zbl 1216.35057) Full Text: Euclid
Girão, Pedro M.; Gomes, José Maria Multibump nodal solutions for an indefinite superlinear elliptic problem. (English) Zbl 1173.35060 J. Differ. Equations 247, No. 4, 1001-1012 (2009). MSC: 35J65 35J20 PDFBibTeX XMLCite \textit{P. M. Girão} and \textit{J. M. Gomes}, J. Differ. Equations 247, No. 4, 1001--1012 (2009; Zbl 1173.35060) Full Text: DOI arXiv
Ackermann, Nils Solution set splitting at low energy levels in Schrödinger equations with periodic and symmetric potential. (English) Zbl 1156.35024 J. Differ. Equations 246, No. 4, 1470-1499 (2009). MSC: 35J60 35J10 35J20 35B05 PDFBibTeX XMLCite \textit{N. Ackermann}, J. Differ. Equations 246, No. 4, 1470--1499 (2009; Zbl 1156.35024) Full Text: DOI
Chan, Whei-Ching C.; Lin, Su-Shing Existence and stability of multibump solutions of an integral-differential equation. (English) Zbl 1160.45005 Int. J. Bifurcation Chaos Appl. Sci. Eng. 17, No. 11, 4099-4115 (2007). Reviewer: Adina Luminiţa Sasu (Timişoara) MSC: 45K05 35R10 92B20 45M10 45M05 PDFBibTeX XMLCite \textit{W.-C. C. Chan} and \textit{S.-S. Lin}, Int. J. Bifurcation Chaos Appl. Sci. Eng. 17, No. 11, 4099--4115 (2007; Zbl 1160.45005) Full Text: DOI
Ackermann, Nils An abstract approach to multibump solutions of periodic Schrödinger equations and applications. (English) Zbl 1224.35112 Nonlinear Anal., Theory Methods Appl., Ser. A, Theory Methods 63, No. 5-7, e1031-e1037 (2005). MSC: 35J60 35B10 47J30 PDFBibTeX XMLCite \textit{N. Ackermann}, Nonlinear Anal., Theory Methods Appl., Ser. A, Theory Methods 63, No. 5--7, e1031--e1037 (2005; Zbl 1224.35112) Full Text: DOI
Budd, C. J.; Rottschäfer, V.; Williams, J. F. Multibump, blow-up, self-similar solutions of the complex Ginzburg-Landau equation. (English) Zbl 1170.35530 SIAM J. Appl. Dyn. Syst. 4, No. 3, 649-678 (2005). MSC: 35Q55 35B20 35B40 35C05 PDFBibTeX XMLCite \textit{C. J. Budd} et al., SIAM J. Appl. Dyn. Syst. 4, No. 3, 649--678 (2005; Zbl 1170.35530) Full Text: DOI
Ding, Yanheng; Luan, Shixia Multiple solutions for a class of nonlinear Schrödinger equations. (English) Zbl 1072.35166 J. Differ. Equations 207, No. 2, 423-457 (2004). Reviewer: Dimitar A. Kolev (Sofia) MSC: 35Q55 35B38 37J45 PDFBibTeX XMLCite \textit{Y. Ding} and \textit{S. Luan}, J. Differ. Equations 207, No. 2, 423--457 (2004; Zbl 1072.35166) Full Text: DOI
van Heerden, Francois A. Homoclinic solutions for a semilinear elliptic equation with an asymptotically linear nonlinearity. (English) Zbl 1142.35422 Calc. Var. Partial Differ. Equ. 20, No. 4, 431-455 (2004). Reviewer: Andrzej Szulkin (Stockholm) MSC: 35J60 35B05 58E05 47J30 PDFBibTeX XMLCite \textit{F. A. van Heerden}, Calc. Var. Partial Differ. Equ. 20, No. 4, 431--455 (2004; Zbl 1142.35422) Full Text: DOI
Rabinowitz, Paul H.; Stredulinsky, Ed Mixed states for an Allen-Cahn type equation. II. (English) Zbl 1161.35397 Calc. Var. Partial Differ. Equ. 21, No. 2, 157-207 (2004). Reviewer: Messoud A. Efendiev (Berlin) MSC: 35J60 58E30 47J30 35J20 PDFBibTeX XMLCite \textit{P. H. Rabinowitz} and \textit{E. Stredulinsky}, Calc. Var. Partial Differ. Equ. 21, No. 2, 157--207 (2004; Zbl 1161.35397) Full Text: DOI
Ackermann, Nils On the multiplicity of sign changing solutions to nonlinear periodic Schrödinger equations. (English) Zbl 1060.35128 Brezis, H. (ed.) et al., Topology methods, variational methods, and their applications. Proceedings of the ICM 2002 satellite conference on nonlinear functional analysis, Taiyuan, China, August 14–18, 2002. River Edge, NJ: World Scientific (ISBN 981-238-262-3/hbk). 1-9 (2003). Reviewer: Messoud A. Efendiev (Berlin) MSC: 35Q55 35B10 PDFBibTeX XMLCite \textit{N. Ackermann}, in: Topology methods, variational methods, and their applications. Proceedings of the ICM 2002 satellite conference on nonlinear functional analysis, Taiyuan, China, August 14--18, 2002. River Edge, NJ: World Scientific. 1--9 (2003; Zbl 1060.35128)
Rabinowitz, P. H. Variational methods for Hamiltonian systems. (English) Zbl 1048.37055 Hasselblatt, B. (ed.) et al., Handbook of dynamical systems. Volume 1A. Amsterdam: North-Holland (ISBN 0-444-82669-6/hbk). 1091-1127 (2002). Reviewer: Thomas J. Bartsch (Gießen) MSC: 37J45 34C25 34C37 58E05 37-02 PDFBibTeX XMLCite \textit{P. H. Rabinowitz}, in: Handbook of dynamical systems. Volume 1A. Amsterdam: North-Holland. 1091--1127 (2002; Zbl 1048.37055)
Alessio, Francesca; Jeanjean, Louis; Montecchiari, Piero Existence of infinitely many stationary layered solutions in \(\mathbb R^2\) for a class of periodic Allen-Cahn equations. (English) Zbl 1125.35342 Commun. Partial Differ. Equations 27, No. 7-8, 1537-1574 (2002). Reviewer: Jörg Härterich (Berlin) MSC: 35J60 34C37 35B10 35B40 35J20 47J30 PDFBibTeX XMLCite \textit{F. Alessio} et al., Commun. Partial Differ. Equations 27, No. 7--8, 1537--1574 (2002; Zbl 1125.35342) Full Text: DOI
Yew, Alice C. Multipulses of nonlinearly coupled Schrödinger equations. (English) Zbl 1021.34036 J. Differ. Equations 173, No. 1, 92-137 (2001). Reviewer: Eugene Ershov (St.Peterburg) MSC: 34C37 37G15 35Q55 37K10 78A60 34C23 PDFBibTeX XMLCite \textit{A. C. Yew}, J. Differ. Equations 173, No. 1, 92--137 (2001; Zbl 1021.34036) Full Text: DOI Link
Bolotin, Sergey V. Heteroclinic chains of skew product Hamiltonian systems. (English) Zbl 0972.37045 Simó, Carles (ed.), Hamiltonian systems with three or more degrees of freedom. Proceedings of the NATO Advanced Study Institute, S’Agaró, Spain, June 19-30, 1995. Dordrecht: Kluwer Academic Publishers. NATO ASI Ser., Ser. C, Math. Phys. Sci. 533, 13-25 (1999). Reviewer: Thomas J.Bartsch (Gießen) MSC: 37J45 34C37 37J15 34C40 PDFBibTeX XMLCite \textit{S. V. Bolotin}, NATO ASI Ser., Ser. C, Math. Phys. Sci. 533, 13--25 (1999; Zbl 0972.37045)
Henrard, Marc Homoclinic and multibump solutions for perturbed second order systems using topological degree. (English) Zbl 0980.34043 Discrete Contin. Dyn. Syst. 5, No. 4, 765-782 (1999). MSC: 34C37 34D10 34C28 34E10 PDFBibTeX XMLCite \textit{M. Henrard}, Discrete Contin. Dyn. Syst. 5, No. 4, 765--782 (1999; Zbl 0980.34043) Full Text: DOI
Alessio, Francesca; Bertotti, Maria Letizia; Montecchiari, Piero Multibump solutions to possibly degenerate equilibria for almost periodic Lagrangian systems. (English) Zbl 0960.70018 Z. Angew. Math. Phys. 50, No. 6, 860-891 (1999). Reviewer: S.Nocilla (Torino) MSC: 70K42 70K55 70H03 34C27 PDFBibTeX XMLCite \textit{F. Alessio} et al., Z. Angew. Math. Phys. 50, No. 6, 860--891 (1999; Zbl 0960.70018) Full Text: DOI
Alessio, Francesca; Caldiroli, Paolo; Montecchiari, Piero Genericity of the multibump dynamics for almost periodic Duffing-like systems. (English) Zbl 0941.34032 Proc. R. Soc. Edinb., Sect. A, Math. 129, No. 5, 885-901 (1999). Reviewer: E.Ershov (St.Peterburg) MSC: 34C28 37J45 34C37 34C27 34D10 PDFBibTeX XMLCite \textit{F. Alessio} et al., Proc. R. Soc. Edinb., Sect. A, Math. 129, No. 5, 885--901 (1999; Zbl 0941.34032) Full Text: DOI
Bolle, P.; Buffoni, B. Multibump homoclinic solutions to a centre equilibrium in a class of autonomous Hamiltonian systems. (English) Zbl 0934.37015 Nonlinearity 12, No. 6, 1699-1716 (1999). Reviewer: Messoud Efendiev (Berlin) MSC: 37C29 37J45 PDFBibTeX XMLCite \textit{P. Bolle} and \textit{B. Buffoni}, Nonlinearity 12, No. 6, 1699--1716 (1999; Zbl 0934.37015) Full Text: DOI
Coti Zelati, Vittorio; Nolasco, Margherita Multibump solutions for Hamiltonian systems with fast and slow forcing. (English) Zbl 0940.37008 Boll. Unione Mat. Ital., Sez. B, Artic. Ric. Mat. (8) 2, No. 3, 585-608 (1999). Reviewer: Serguei Zelik (Moskva) MSC: 37D45 37J05 PDFBibTeX XMLCite \textit{V. Coti Zelati} and \textit{M. Nolasco}, Boll. Unione Mat. Ital., Sez. B, Artic. Ric. Mat. (8) 2, No. 3, 585--608 (1999; Zbl 0940.37008) Full Text: EuDML
Montecchiari, Piero; Nolasco, Margherita; Terracini, Susanna A global condition for periodic Duffing-like equations. (English) Zbl 0926.37005 Trans. Am. Math. Soc. 351, No. 9, 3713-3724 (1999). MSC: 37C29 37B40 34C37 37J45 PDFBibTeX XMLCite \textit{P. Montecchiari} et al., Trans. Am. Math. Soc. 351, No. 9, 3713--3724 (1999; Zbl 0926.37005) Full Text: DOI
Alessio, Francesca; Montecchiari, Piero Multibump solutions for a class of Lagrangian systems slowly oscillating at infinity. (English) Zbl 0919.34044 Ann. Inst. Henri Poincaré, Anal. Non Linéaire 16, No. 1, 107-135 (1999). Reviewer: E.Ershov (St.Peterburg) MSC: 34C37 37D99 58E05 70H05 PDFBibTeX XMLCite \textit{F. Alessio} and \textit{P. Montecchiari}, Ann. Inst. Henri Poincaré, Anal. Non Linéaire 16, No. 1, 107--135 (1999; Zbl 0919.34044) Full Text: DOI Numdam EuDML
Berti, Massimiliano; Bolle, Philippe Variational construction of homoclinics and chaos in presence of a saddle-saddle equilibrium. (English) Zbl 0938.34039 Ann. Sc. Norm. Super. Pisa, Cl. Sci., IV. Ser. 27, No. 2, 331-377 (1998). Reviewer: E.Ershov (St.Peterburg) MSC: 34C37 37D45 34C28 37J45 PDFBibTeX XMLCite \textit{M. Berti} and \textit{P. Bolle}, Ann. Sc. Norm. Super. Pisa, Cl. Sci., IV. Ser. 27, No. 2, 331--377(1999) (1998; Zbl 0938.34039) Full Text: Numdam EuDML
Berti, Massimiliano; Bolle, Philippe Variational construction of homoclinics and chaos in presence of a saddle-saddle equilibrium. (English) Zbl 0921.58023 Atti Accad. Naz. Lincei, Cl. Sci. Fis. Mat. Nat., IX. Ser., Rend. Lincei, Mat. Appl. 9, No. 3, 167-175 (1998). Reviewer: Messoud Efendiev (Berlin) MSC: 37J99 PDFBibTeX XMLCite \textit{M. Berti} and \textit{P. Bolle}, Atti Accad. Naz. Lincei, Cl. Sci. Fis. Mat. Nat., IX. Ser., Rend. Lincei, Mat. Appl. 9, No. 3, 167--175 (1998; Zbl 0921.58023) Full Text: arXiv
Rabinowitz, Paul H. A multibump construction in a degenerate setting. (English) Zbl 0876.34055 Calc. Var. Partial Differ. Equ. 5, No. 2, 159-182 (1997). Reviewer: Th.J.Bartsch (Gießen) MSC: 34C37 37J99 58E05 PDFBibTeX XMLCite \textit{P. H. Rabinowitz}, Calc. Var. Partial Differ. Equ. 5, No. 2, 159--182 (1997; Zbl 0876.34055) Full Text: DOI
Musso, Monica; Passaseo, Donato Nonlinear elliptic problems approximating degenerate equations. (English) Zbl 0891.35037 Nonlinear Anal., Theory Methods Appl. 30, No. 8, 5071-5076 (1997). Reviewer: K.Pflüger (Berlin) MSC: 35J65 35B40 35J70 PDFBibTeX XMLCite \textit{M. Musso} and \textit{D. Passaseo}, Nonlinear Anal., Theory Methods Appl. 30, No. 8, 5071--5076 (1997; Zbl 0891.35037) Full Text: DOI
Montecchiari, Piero; Nolasco, Margherita; Terracini, Susanna Multiplicity of homoclinics for a class of time recurrent second order Hamiltonian systems. (English) Zbl 0886.58014 Calc. Var. Partial Differ. Equ. 5, No. 6, 523-555 (1997). MSC: 58E05 34C37 70H05 37D99 PDFBibTeX XMLCite \textit{P. Montecchiari} et al., Calc. Var. Partial Differ. Equ. 5, No. 6, 523--555 (1997; Zbl 0886.58014) Full Text: DOI
Montecchiari, Piero Multiplicity results for a class of semilinear elliptic equations on \(\mathbb{R}^ m\). (English) Zbl 0866.35043 Rend. Semin. Mat. Univ. Padova 95, 217-252 (1996). Reviewer: S.Tersian (Russe) MSC: 35J65 35J20 PDFBibTeX XMLCite \textit{P. Montecchiari}, Rend. Semin. Mat. Univ. Padova 95, 217--252 (1996; Zbl 0866.35043) Full Text: Numdam EuDML
Rabinowitz, Paul H. A variational approach to multibump solutions of differential equations. (English) Zbl 0874.58019 Saari, Donald G. (ed.) et al., Hamiltonian dynamics and celestial mechanics. A joint summer research conference, June 25–29, 1995, Seattle, WA, USA. Providence, RI: American Mathematical Society. Contemp. Math. 198, 31-43 (1996). Reviewer: Ding Tongren (Beijing) MSC: 37J99 34C37 35J60 PDFBibTeX XMLCite \textit{P. H. Rabinowitz}, Contemp. Math. 198, 31--43 (1996; Zbl 0874.58019)
Montecchiari, Piero; Nolasco, Margherita Multibump solutions for perturbations of periodic second order Hamiltonian systems. (English) Zbl 0863.34050 Nonlinear Anal., Theory Methods Appl. 27, No. 12, 1355-1372 (1996). Reviewer: Chen Lan Sun (Beijing) MSC: 34C37 37J99 PDFBibTeX XMLCite \textit{P. Montecchiari} and \textit{M. Nolasco}, Nonlinear Anal., Theory Methods Appl. 27, No. 12, 1355--1372 (1996; Zbl 0863.34050) Full Text: DOI
Rabinowitz, Paul H. Multibump solutions of differential equations: An overview. (English) Zbl 0968.37019 Chin. J. Math. 24, No. 1, 1-36 (1996). MSC: 37J45 34C37 37-02 58E05 35J60 70H05 PDFBibTeX XMLCite \textit{P. H. Rabinowitz}, Chin. J. Math. 24, No. 1, 1--36 (1996; Zbl 0968.37019)
Abenda, Simonetta; Caldiroli, Paolo; Montecchiari, Piero Multibump solutions for Duffing-like systems. (English) Zbl 0880.34045 Rend. Ist. Mat. Univ. Trieste 28, No. 1-2, 115-143 (1996). Reviewer: G.Osipenko (St.Peterburg) MSC: 34C37 PDFBibTeX XMLCite \textit{S. Abenda} et al., Rend. Ist. Mat. Univ. Trieste 28, No. 1--2, 115--143 (1996; Zbl 0880.34045)
Séré, Eric Multibump solutions and topological entropy. (English) Zbl 0843.34049 Ambrosetti, Antonio (ed.) et al., Variational methods in nonlinear analysis. Papers presented during the 14th course, Erice, Sicily, Italy, May 12-20, 1992. Basel: Gordon and Breach Publishers. 161-171 (1995). MSC: 34C37 37J99 PDFBibTeX XMLCite \textit{E. Séré}, in: Variational methods in nonlinear analysis. Papers presented during the 14th course, Erice, Sicily, Italy, May 12-20, 1992. Basel: Gordon and Breach Publishers. 161--171 (1995; Zbl 0843.34049)
Rabinowitz, Paul H. Multibump solutions for an almost periodically forced singular Hamiltonian system. (English) Zbl 0828.34034 Electron. J. Differ. Equ. 1995, No. 12, 21 p. (1995). MSC: 34C37 90C99 58E99 37J45 PDFBibTeX XML Full Text: EuDML EMIS
Caldiroli, Paolo; Montecchiari, Piero Homoclinic orbits for second order Hamiltonian systems with potential changing sign. (English) Zbl 0867.70012 Commun. Appl. Nonlinear Anal. 1, No. 2, 97-129 (1994). MSC: 70H05 34C37 37J99 PDFBibTeX XMLCite \textit{P. Caldiroli} and \textit{P. Montecchiari}, Commun. Appl. Nonlinear Anal. 1, No. 2, 97--129 (1994; Zbl 0867.70012)
Coti Zelati, Vittorio; Rabinowitz, Paul H. Multibump periodic solutions of a family of Hamiltonian systems. (English) Zbl 0819.34028 Topol. Methods Nonlinear Anal. 4, No. 1, 31-57 (1994). Reviewer: A.Kachurovskij (Novosibirsk) MSC: 34C25 34C37 PDFBibTeX XMLCite \textit{V. Coti Zelati} and \textit{P. H. Rabinowitz}, Topol. Methods Nonlinear Anal. 4, No. 1, 31--57 (1994; Zbl 0819.34028) Full Text: DOI
Rabinowitz, Paul H. Multibump solutions of a semilinear elliptic PDE on \(\mathbb{R}^ n\). (English) Zbl 0792.35050 Ni, Wei-Ming (ed.) et al., Degenerate diffusions. Proceedings of the IMA workshop, held at the University of Minnesota, MN, USA, from May 13 to May 18, 1991. New York: Springer-Verlag. IMA Vol. Math. Appl. 47, 175-185 (1993). Reviewer: P.Drábek (Plzeň) MSC: 35J60 35A05 35D10 PDFBibTeX XMLCite \textit{P. H. Rabinowitz}, IMA Vol. Math. Appl. 47, 175--185 (1993; Zbl 0792.35050)