G. Opfer

Neuere Veröffentlichungen

Buchveröffentlichung

• Numerische Mathematik für Anfänger, 5. Auflage, Vieweg+Teubner, Wiesbaden, 2008, xix+392 S.

• Fehlerliste der 3. Auflage

Herausgegebene Bücher

• W. Gautschi, G. H. Golub, G. Opfer (Hrsg.): Applications and Computation of Orthogonal Polynomials,
  Birkhäuser, Basel, Boston, Berlin,1999, 268 S., ISNM 131.
  Conference at the Mathematical Research Institute Oberwolfach, Germany, March 22-28, 1998.
  Dedicated to the Memory of Günther Hämmerlin (1928 - 1997).

Originalarbeiten

• An analytic approach to the Collatz 3n + 1 problem for negative start values with an appendix of tables,
  Hamburger Beiträge zur Angewandten Mathematik, Preprint 2012-11, December 2012, 40 p.
• An analytic approach to the Collatz 3n + 1 problem,
  Hamburger Beiträge zur Angewandten Mathematik, Preprint 2011-09, May 2011, 32 p.
• The Nonexistence of Pseudoquaternions in $\C\power{2\times2}$,
  jointly with Drahoslava Janovská.
  Advances in Applied Clifford Algebras, 21 (2011), 531-540, published online: December 24, 2010.
  Hamburger Beiträge zur Angewandten Mathematik, Preprint 2010-11, Oktober 2010, 8 p.
• The classification and the computation of the zeros of quaternionic, two-sided polynomials,
  jointly with Drahoslava Janovská.
  Numer. Math., 115 (2010), 81-100, published online: November 18, 2009.
• A note on the computation of all zeros of simple quaternionic polynomials,
  jointly with Drahoslava Janovská.
  SIAM J. Numer. Anal. 48 (2010), 244-256, published online: April 2, 2010.
• Polynomials and Vandermonde Matrices over the Field of Quaternions,
  ETNA 36(2009), 9-16.
  
• Linear equations in quaternionic variables,
  gemeinsam mit Drahoslava Janovská.
  Mitt. Math. Ges. Hamburg, 27 (2008), 223-234.
  
• On Disk-Like Sets and Square Coverings in the Plane - a Geometric Problem,
  Dedicated to Richard S. Varga on the occasion of his 80th birthday.
  Result. Math. 53 (2009), 349-359, Birkhäuser, Basel.
• Decompositions of Quaternions and their Matrix Equivalents,
  gemeinsam mit Drahoslava Janovská.
  Dedicated to the Memory of Gene Golub.
  Preprint, Hamburger Beiträge zur Angewandten Mathematik,
  2008-02, March 2008, 9 p.
  in V. Olshevsky and E. Tyrtyshnikov (eds.): Matrix Methods: Theory, Algorithms and Applications, World Scientific, New Jersey, 2010, pp. 20-30.
  Proceedings of 2nd INTERNATIONAL CONFERENCE ON MATRIX METHODS AND OPERATOR EQUATIONS, July 23-27, 2007, Moscow, Russia.
  
• On one linear equation in one quaternionic unknown,
  gemeinsam mit Drahoslava Janovská,
  Dedicated to Bernd Fischer on the occasion of his 50th birthday.
  Preprint, Hamburger Beiträge zur Angewandten Mathematik,
  2007-14, September 2007, 34 S.
  Submitted to Linear Algebra Appl. (but rejected).
  
• Computing Quaternionic Roots by Newton's Method,
  gemeinsam mit Drahoslava Janovská,
  Preprint, Hamburger Beiträge zur Angewandten Mathematik,
  Reihe A, 194, December 2006, 29 S.
  ETNA 26(2007), 82-102.
  
• Linear equations in quaternions,
  gemeinsam mit Drahoslava Janovská,
  Preprint, Hamburger Beiträge zur Angewandten Mathematik,
  Reihe A, 193, Mai 2006, 9 S.
  Numerical Mathematics and Advanced Applications, Proceedings of ENUMATH 2005,
  A. B. de Castro, D. G\'omez, P. Quintela, and P. Salgado (eds.),
  Springer, Berlin, Heidelberg, New York, 2006, 945-953, ISBN 3-540-34287-7.
  
• Shift Generated Haar Spaces on Track Fields,
  dedicated to the memory of Walter Hengartner.
  Preprint, Hamburger Beiträge zur Angewandten Mathematik,
  Reihe A, 191, March 2006, 12 S.
  Abstract in English and Armenian.
  Journal of Contemporary Mathematical Analysis, 40, 6, 2005, 41-53.
  The editor, A. Sahakian, has shortened the abstract and deleted the Armenian version of the abstract without consent of the author.
  Proceedings of a conference on Harmonic Analysis and Approximation, III
  in Tsakhadzor, Armenia, September 21-26, 2005. Academy of Science, Erivan.
• On the Number 50,
  dedicated to Marie Luise and Reiner Lauterbach on the occasion of their 50th birthday.
  Preprint, Hamburger Beiträge zur Angewandten Mathematik,
  Reihe A, 188, October 2005, 32 S.
  Mitt. Math. Ges. 24(2005), 151-174.
• Fast Givens transformation for quaternion valued matrices applied to Hessenberg reductions,
  gemeinsam mit Drahoslava Janovská,
  Preprint, Hamburger Beiträge zur Angewandten Mathematik,
  Reihe A, 184, February 2005, 35 S.
  ETNA 20(2005), 1-26.
  
• The conjugate gradient algorithm applied to quaternion-valued matrices,
  Preprint, Hamburger Beiträge zur Angewandten Mathematik,
  Reihe A, 179, March 2004, 28 S.
  ZAMM 85(2005)9, 660-672.
  
• Shift generated Haar spaces on unbounded, closed domains in the complex plane,
  Dedicated to the memory of Dieter Gaier,
  gemeinsam mit Maude Giasson und Walter Hengartner,
  Preprint, Hamburger Beiträge zur Angewandten Mathematik,
  Reihe A, 175, August 2003, 14 S.
  Computational Methods and Function Theory, 3 (2003), 151 - 164.
  
• Shift generated Haar spaces on compact domains in the complex plane ,
  gemeinsam mit Walter Hengartner,
  Preprint, Hamburger Beiträge zur Angewandten Mathematik,
  Reihe A, 174, July 2003, 18 S.
  Constr. Approx. 22(2005), 113 - 132.
  
• Givens' Transformation Applied to Quaternion Valued Vectors ,
  gemeinsam mit Drahoslava Janovská,
  Preprint, Hamburger Beiträge zur Angewandten Mathematik,
  Reihe A, 171, February 2003, 12 S.
  BIT Numerical Mathematics, 43 (2003), 991 - 1002.
  
• Complex Haar Spaces Generated by Shifts Applied to a Single Function ,
  with Walter Hengartner,
  Preprint, Hamburger Beiträge zur Angewandten Mathematik,
  Reihe A, 167, November 2001, 14 S.
  has appeared in: C. K. Chui, L. L. Schumaker, J. Stöckler (eds.),
  Approximation Theory X, Abstract and Classical Analysis, pp. 223-238 (2002).
  Vanderbilt University Press, Nashville, TN.
  ISBN 0-8265-1415-4.
  
• Hyperbolic Householder and Givens Transformations,
  gemeinsam mit Drahoslava Janovská,
  Preprint, Hamburger Beiträge zur Angewandten Mathematik,
  Reihe A, 136, March 1998, 19 S.
  A note on hyperbolic transformations, Numer. Linear Algebra Appl., 8 (2001), 127-146.
  The following MATLAB-Programs are referred to in the text:
  Hypgiv.m, Hyphsd.m, Qrhg.m, Vechg.m, Vechh.m, Zerogiv.m, Zerohh.m.
• Complex version of Catalan's problem,
  gemeinsam mit Wolfgang Ripken,
  Mitt. Math. Ges. Hamburg, 17 (1998), 101-112.
• On the Construction of Optimal Monotone Cubic Spline Interpolation,
  gemeinsam mit Sigrid Fredenhagen und Hans Joachim Oberle,
  J. Approx. Theory 96 (1999), 182-201.
• Non-negative splines, in particular of degree five,
  gemeinsam mit Hans Joachim Oberle, Numer. Math. 79 (1998), 427-450.
• Splines with prescribed modified moments,
  gemeinsam mit Hans Joachim Oberle, in: Curves and surfaces in geometric design,
  P.-J. Laurent, A. Le M'ehaut'e, L. L. Schumaker (Eds.), 343-352, 1994.
• On the number of integer dilation matrices used in wavelet theory,
  in: Proceedings of the Cornelius Lanczos international centenary conference, J. D. Brown, M. T. Chu, D. C. Ellison, R. J. Plemmons (Eds.), SIAM, Philadelphia, 1994, 426-428.
• Faber versus minimal polynomials on annular sectors,
  gemeinsam mit Jan Modersitzki, Computational Methods and Function Theory 1994,
  R. M. Ali, St. Ruscheweyh, E. B. Saff (Eds.), World Scientific, Singapore, 1995, 243-265.
• Display of zeros of orthogonal polynomials on annular sectors,
  Hamburger Beiträge zur Angewandten Mathematik, Reihe A, 87, Oktober 1994.

  ---

  opfer@math.uni-hamburg.de, 19. März 2012