Maximal abelian subgroups of spinor groups and error-correcting codes, in Algebraic Topology, Mark Mahowald, Stewart Priddy, eds., Contemporary Mathematics, vol. 96, 1989, pp. 333--350.

Self-orthogonal codes and the topology of the spinor groups, in Coding Theory and Design Theory, Part I, Coding Theory, D. Ray-Chaudhuri, ed., IMA volumes in Mathematics and its Applications, volume 20, Springer-Verlag, New York, 1990, pp. 219--239.

Witt's extension theorem for mod four valued quadratic forms, Trans. Amer. Math. Soc., 336 (1993) 445--461.

With Harold N. Ward , Characters and the equivalence of codes, J. Combin. Theory, series A, 73 (1996) 348--352.

Extension theorems for linear codes over finite rings, in Applied Algebra, Algebraic Algorithms and Error-Correcting Codes, T. Mora, H. Mattson, eds., LNCS 1255, Berlin: Springer-Verlag, 1997, pp. 329--340. (Proceedings of 12th International Symposium, AAECC-12, Toulouse, France, June 23--27, 1997.) ( dvi , ps , pdf )

Weight functions and the extension theorem for linear codes over finite rings, in Finite Fields: Theory, Applications and Algorithms, R. C. Mullin, G. L. Mullen, eds., Contemp. Math. 225, Providence: Amer. Math. Soc., 1999, 231--243. (Proceedings of the Fourth International Conference on Finite Fields: Theory, Applications and Algorithms, August 12--15, 1997, University of Waterloo, Waterloo, Ontario, Canada.) ( dvi , ps , pdf )

Duality for modules over finite rings and applications to coding theory, Amer. J. Math., 121 (1999), 555-575. ( dvi , ps , pdf ; also, pdf version available from Amer. J. Math for subscribers to MUSE)

Factoring the semigroup determinant of a finite commutative chain ring, in Coding Theory, Cryptography and Related Areas, J. Buchmann, T. Hoholdt, H. Stichtenoth, and H. Tapia-Recillas, eds., Springer-Verlag, Berlin, 2000, pp. 249--259. (Proceedings of the International Conference on Coding Theory and Cryptography, Guanajuato, Mexico, 1998.) ( dvi , ps , pdf )

The structure of linear codes of constant weight, Trans. Amer.
Math. Soc. 354 (2002), 1007-1026. ( pdf
;
from
the
AMS, click
here .)

"Foundations of linear codes defined over finite modules: the extension theorem and the MacWilliams identities," which appears in the proceedings volume: Codes over Rings, Proceedings of the CIMPA Summer School, Ankara, Turkey, 18--29 August 2008, Patrick Solé, editor, Series on Coding Theory and Crytology, Vol. 6, World Scientific, Singapore, 2009, pp. 124--190. ( pdf )

Anti-isomorphisms, character modules and self-dual codes over non-commutative rings, Int. J. Information and Coding Theory, 1 (4) (2010), 429-444. (Contained in a special volume in honor of Vera Pless.) ( pdf )

Applications of Finite Frobenius Rings to the Foundations of Algebraic Coding Theory, in the Proceedings of the 44th Symposium on Ring Theory and Representation Theory (Okayama University, Japan, September 25-27, 2011), O. Iyama, ed., Nagoya, Japan, 2012, pp. 223-245 ( pdf ).

Relative one-weight linear codes, Designs, Codes and Cryptography, 72 (2) (2014), 331-344. DOI 10.1007/s10623-012-9769-0. ( pdf ; from the journal, click here )

With Marcus Greferath, Thomas Honold, Cathy Mc Fadden, and Jens Zumbragel, MacWilliams' Extension Theorem for Bi-Invariant Weights over Finite Principal Ideal Rings, J. Combin. Theory, series A, 125C (2014), 177-193. DOI 10.1016/j.jcta.2014.03.005. ( pdf ; from the journal, click here )

Some applications of the Fourier transform in algebraic coding theory, in Algebra for Secure and Reliable Communication Modeling, M. Lahyane, E. Martinez-Moro, eds., Contemp. Math. 642, Providence: Amer. Math. Soc., 2015, 1--40. (CIMPA Research School and Conference, Algebra for Secure and Reliable Communication Modeling, October 1–13, 2012, Morelia, State of Michoacán, Mexico.) ( pdf ; from the AMS with subscription, click here )

With Noha ElGarem and Nefertiti Megahed, The extension theorem with respect to symmetrized weight compositions, in Coding Theory and Applications, R. Pinto, P. Rocha Malonek, P. Vettori, eds., CIM Series in Mathematical Sciences, vol. 3, Springer, 2015, 177--183. (4th International Castle Meeting, Palmela Castle, Portugal, September 15--18, 2014.) ( pdf ; from Springer with subscription, click here )

With Serhii Dyshko and Philippe Langevin, Deux analogues au determinant de Maillet, Comptes Rendus Math. Acad. Sci. Paris, 354 (7) (2016), 649-652. ( pdf )

With Steve Szabo, Properties of dual codes defined by nondegenerate forms, J. Algebra Combin. Discrete Appl., 4 (2) (2017), 105--113 (proceedings of the 2015 Lens conference NCRA IV). ( pdf ; from the journal, click here )

With Philippe Langevin, The extension problem for Lee and Euclidean weights, J. Algebra Combin. Discrete Appl., 4 (2) (2017), 207--217 (proceedings of the 2015 Lens conference NCRA IV). ( pdf ; from the journal, click here )

Isometry groups of additive codes over finite fields, Journal of Algebra and its Applications, 17 (10) (2018), paper 1850198, 39 pages. ( pdf ) https://doi.org/10.1142/S0219498818501980

With Philippe Langevin, The Extension Theorem for the Lee and Euclidean Weights over Z/p^k Z, Journal of Pure and Applied Algebra, 223 (3) (2019), 922--930. ( pdf ) https://doi.org/10.1016/j.jpaa.2018.05.006

With Oliver W. Gnilke, Marcus Greferath, Thomas Honold, and Jens Zumbragel, The extension theorem for bi-invariant weights over Frobenius rings and Frobenius bimodules, in Rings, Modules and Codes, A. Leroy, C. Lomp, S. Lopez-Permouth, and F. Oggier, eds., Contemp. Math. 727, Providence: American Math. Soc., 2019, 117--129 (proceedings of the 2017 Lens conference NCRA V). ( pdf ) https://doi.org/10.1090/conm/727/14629

With Noha Abdelghany, Failure of the MacWilliams identities for the Lee weight enumerator over Z_m, m \geq 5, Discrete Mathematics, 343 (11) (2020), article 112036, 12 pages. ( pdf ) https://doi.org/10.1016/j.disc.2020.112036

Two approaches to the extension problem for arbitrary weights over finite module alphabets, revised September 2020. ( pdf ) “This is a post-peer-review, pre-copyedit version of an article published in Applicable Algebra in Engineering, Communication and Computing. The final authenticated version is available online at: http://dx.doi.org/10.1007/s00200-020-00465-5 .”

With Serhii Dyshko, MacWilliams extension property for arbitrary weights on linear codes over module alphabets, Designs, Codes and Cryptography, (2021). ( pdf under old title) ``This preprint has not undergone peer review (when applicable) or any post-submission improvements or corrections. The Version of Record of this article is published in Designs, Codes and Cryptography, and is available online at https://doi.org/10.1007/s10623-021-00945-w.''

Homogeneous weight enumerators over integer residue rings and failures of the MacWilliams identities, Revista de la Union Matematica Argentina, (2022), 20 pages, to appear. ( pdf ) https://doi.org/10.33044/revuma.2807

Codes of constant Lee or Euclidean weight, extended abstract for the Workshop on Coding and Cryptography , Paris, 1999. ( dvi , ps , pdf ) Slides for my talk. ( dvi , ps , pdf )

Witt theorems for linear codes over finite Frobenius rings. These are slides of my talk at the International Conference on Algebra and its Applications, Athens, Ohio, March 27, 1999. ( dvi , ps , pdf )

Linear codes over Z/(2^k) of constant Euclidean weight, Proceedings of the Thirty-Seventh Annual Allerton Conference on Communication, Control, and Computing, University of Illinois, 1999, pp. 895--896. ( dvi , ps , pdf ) Slides for my talk. ( dvi , ps , pdf ) Finally, a long version of the paper containing material on orbit structures and a uniqueness theorem. ( dvi , ps , pdf )

Understanding linear codes of constant weight using virtual linear codes, Proceedings of the Thirty-Eighth Annual Allerton Conference on Communication, Control, and Computing, University of Illinois, 2000, pp. 1038--1046. ( pdf ) Slides for my talk. ( pdf )

The structure of linear codes of constant weight, Proceedings of the International Workshop on Coding and Cryptography , D. Augot, C. Carlet, eds., INRIA, Paris, 2001, pp. 547--556. ( pdf ) Slides for my talk. ( pdf )

The development of coding theory over finite rings. Slides
for my talk in the special session on Algebraic Coding Theory at
the Joint Mathematics Meetings, San Diego, California, January 7,
2002. ( pdf
)

Restrictions on two-weight projective linear codes. Proceedings of the International Workshop on Coding and Cryptography , INRIA, Versailles, March 24-28, 2003. ( N/A ) Slides for my talk, March 28, 2003. ( pdf )

An essay on equivalence of linear codes. Slides for my talk in the special session on Applications of Number Theory and Algebraic Geometry to Coding at the AMS sectional meeting in Boulder, Colorado, October 4, 2003. ( pdf )

A essay on equivalence of linear codes, II. Slides for my
talk in the special session on Algebraic Coding Theory at the AMS
sectional meeting in Athens, Ohio, March 26, 2004. ( pdf )

A essay on equivalence of linear codes, III. Slides for my
talk in the special session on Coding Theory and Cryptography at
the AMS/SMM international joint meeting in Houston, Texas, May 14,
2004. ( pdf )

Highly symmetric weight functions on matrix rings. Slides
for my talk in the special session on Codes and Applications at
the AMS sectional meeting in Evanston, Illinois, October 23,
2004. ( pdf )

Code equivalence and finite Frobenius rings. Slides for my
talk in the Theory of Rings and Modules section of the 28th Ohio
State-Denison Conference, Columbus, Ohio, May 19, 2006. ( pdf )

Equivalence of linear codes over finite rings (in honor of Vera
Pless). Slides for my talk in the special session on
Algebraic Coding Theory---Honoring the Retirement of Vera Pless at
the AMS sectional meeting in Cincinnati, Ohio, October 22,
2006. ( pdf )

Character-theoretic proofs of equivalence theorems (in honor of
Thann Ward). Slides for my talk in the special session on
Algebraic Coding Theory (in honor of Harold N. Ward's retirement)
at the AMS sectional meeting in Chicago, Illinois, October 6,
2007. ( pdf
)

Dual codes over finite rings---cautions and compromises.
Slides for my talk in the special session on Algebraic Aspects of
Coding Theory at the AMS sectional meeting in Bloomington,
Indiana, April 5, 2008. ( pdf )

Lecture notes on linear codes defined over finite modules: the extension theorem and the MacWilliams identities. Draft version of August 14, 2008 ( pdf ). For the use of the CIMPA-UNESCO-TUBITAK Summer School on Codes over Rings, Middle East Technical University, Ankara, Turkey, August 18-29, 2008. Revised, final version of May 19, 2009: "Foundations of linear codes defined over finite modules: the extension theorem and the MacWilliams identities." (See above.)

The use of Frobenius rings in coding theory: a personal
view. Slides for my talk in the special session on Linear
Codes over Rings and Modules at the AMS sectional meeting in
Kalamazoo, Michigan, October 18, 2008. (Some of the slides
are from the Bloomington talk above.) ( pdf )

Lecture notes on the MacWilliams identities and the extension
theorem, for the CIMAT International
School
and
Conference
on Coding Theory, CIMAT, Guanajuato, Mexico,
November 28 - December 4, 2008. Draft version of November
25, 2008 ( pdf ).

Lecture notes on the MacWilliams identities and self-dual codes
over non-commutative rings, for the Workshop on
Coding Theory and Geometry of Rational Surfaces, Instituto
de Física y Matemáticas, Universidad Michoacana de San Nicolás de
Hidalgo, Morelia, Michoacán, México, September 23 - 26,
2009. Draft version of September 23, 2009 ( pdf ).

Ring involutions and self-dual codes. Slides for my talk in the
special session on Advances in Algebraic Coding Theory at the AMS
sectional meeting in Lexington, Kentucky, March 27, 2010.
( pdf
) Some photos, courtesy of Jon-Lark Kim:
1 , 2 .

Lecture series: Two Fundamental Theorems of MacWilliams,
Huazhong Normal University, Wuhan, Hubei, China, June-July
2011. Lecture one, June 22, 2011: The classical case over
finite fields ( pdf
). Lecture two, June 28, 2011: The MacWilliams identities
over finite rings ( pdf
). Lecture three, July 2, 2011: The MacWilliams
extension theorem over finite rings ( pdf ).

The MacWilliams Identities. Slides for a lecture primarily
for undergraduates at the Huangshi Institute of Technology,
Huangshi, Hubei, China, June 24, 2011. ( pdf )

Finite Frobenius Rings as a Setting for Algebraic Coding
Theory. Slides for a lecture at the Hefei University of
Technology, Hefei, Anhui, China, June 30, 2011. ( pdf )

Two lectures on the theme: Applications of Finite Frobenius Rings to Algebraic Coding Theory. Symposium on Ring and Representation Theory Japan, Okayama University. Lecture one, September 25, 2011: Two Theorems of MacWilliams over Finite Frobenius Rings ( pdf ). Lecture two, September 26, 2011: Using Coding Theory to Characterize Finite Frobenius Rings ( pdf ). Survey paper prepared for the Symposium: Applications of Finite Frobenius Rings to the Foundations of Algebraic Coding Theory. (See above.)

Relative One-Weight Codes. Slides for my talk in the special session on Coding Theory at the AMS sectional meeting in Lincoln, Nebraska, October 14, 2011. ( pdf )Characterizing Finite Frobenius Rings Via Coding Theory. Slides for a lecture in the Algebra and Communications Seminar, University College Dublin, Dublin, Ireland, November 7, 2011. ( pdf )

Finite Frobenius Rings and the MacWilliams Identities. Slides for a lecture in the Algebra and Communications Seminar, University College Dublin, Dublin, Ireland, November 14, 2011. ( pdf )

The MacWilliams Identities. Slides for the department colloquium at Western Michigan University, Kalamazoo, MI, March 1, 2012. ( pdf )

Lecture series for the research school Algebra for Secure and Reliable Communication Modeling, Morelia, Michoacan, Mexico, October 2012. Linear codes over finite rings and modules, October 5, 2012: ( pdf ). Characters and the MacWilliams identities, October 8, 2012: ( pdf ). Characters and finite Frobenius rings, October 9, 2012: ( pdf ). Ring involutions and self-dual codes, October 9, 2012: ( pdf ). Quasi-cyclic codes, October 12, 2012: ( pdf ). Equivalence of codes: sufficient conditions, October 12, 2012: ( pdf ). Equivalence of codes: necessary conditions, October 13, 2012: ( pdf ). Equivalence of codes: general weights, October 13, 2012: ( pdf ).

Lecture series, Linear codes over finite rings and modules, for the Coding Theory Seminar at Eastern Kentucky University, Richmond, Kentucky, March 2013. The MacWilliams identities, March 4, 2013: ( pdf ). The MacWilliams extension theorem over Frobenius rings, March 5, 2013 (Emily day!): ( pdf ). The MacWilliams extension theorem for general weights, March 6, 2013: ( pdf )

Exotic Automorphisms of Additive Codes. Slides for my talk in the special session on Algebraic Coding Theory at the AMS sectional meeting in Louisville, Kentucky, October 5, 2013. ( pdf )

Automorphisms of Additive Codes. Slides for my talk in the Ring Theory Session of the 32nd Ohio State-Denison Mathematics Conference, Columbus, Ohio, May 9, 2014. ( pdf )

Lecture series (mini-cours), Linear codes from the axiomatic viewpoint, for the conference Noncommutative rings and their applications IV, Lens, France, June 2015. Overview and characters, June 8, 2015: ( pdf ). MacWilliams identities, June 8, 2015: ( pdf ). MacWilliams extension theorem and converse, June 9, 2015: ( pdf ). MacWilliams extension theorem for other weights, June 9, 2015: ( pdf ). Isometries of additive codes, June 10, 2015: ( pdf ). One-weight and relative one-weight codes, June 10, 2015: ( pdf ). Self-duality for linear codes over modules, June 11, 2015: ( pdf ). Simplicial complexes coming from linear codes, June 11, 2015: ( pdf ).

Isometry Groups of Additive Codes. Slides for my talk in the special session on Coding Theory and its Applications at the AMS sectional meeting at Loyola University, Chicago, Illinois, October 4, 2015. ( pdf )

Mini-course, Foundational aspects of linear codes, for the workshop On the Algebraic and Geometric Classifications of Projective Varieties, Messina, Sicily, June 20-24, 2016. Characters and Frobenius rings: ( pdf ). Fourier transform and good duality: ( pdf ). Extension property: sufficient conditions: ( pdf ). Extension property: necessary conditions: ( pdf ). Research seminar, Isometry groups of additive codes: ( pdf ).

The Extension Theorem for Lee Weight. Slides for my talk in the special session on Advances in Algebraic Coding Theory at the AMS sectional meeting at the University of St. Thomas, Minneapolis, Minnesota, October 29, 2016. (pdf )

Lecture series (course), Character-theoretic tools for studying linear codes over rings and modules, for the CIMPA research school Algebraic Methods in Coding Theory, Ubatuba, Brazil, July 2017. Linear Codes over Finite Fields, July 3, 2017: ( pdf ). Additive Codes and Characters, July 4: ( pdf ). Duality for linear codes, July 5: ( pdf ). Self-duality for linear codes over modules, July 6: ( pdf ). MacWilliams extension theorem and converse, July 10: ( pdf ). MacWilliams extension theorem for other weights, July 11: ( pdf ). Isometries of additive codes, July 12: ( pdf ). Using semi-group rings, July 13: ( pdf ). Extension Problem for general weights, July 14: ( pdf ).

The extension theorem for Lee weight using Dirichlet L-functions. Slides for my talk in the Algebra Seminar, Department of Mathematics, University of Sao Paulo, Sao Paulo, Brazil, July 17, 2017: ( pdf ).

Groups of isometries of additive codes over GF(q). Slides for my talk in the special session on Finite Algebraic Combinatorics and Applications, Mathematical Congress of the Americas, Montreal, Quebec, Canada, July 28, 2017: ( pdf ).

Lecture series (course), Foundational results on linear codes over rings and modules, for the academic event "Some Topics in Algebraic Geometry and Linear Codes" sponsored by the Institute of Physics and Mathematics of the University of Michoacan, Morelia, March 5--9, 2018. 1. Codes and their duals, March 5: ( pdf ). 2. Additive codes and their duals, March 6: ( pdf ). 3. Linear codes and their duals, March 7: ( pdf ). 4. The extension problem for Hamming weight, March 8: ( pdf ). Research seminar, The extension theorem for Lee and Euclidean weights, March 9: ( pdf ).

Lecture series, Linear Codes over Finite Rings and Modules, Central China Normal University, May 2018. Lecture 1: Linear codes over finite fields ( pdf ). 2: Representations and characters ( pdf ). 3: Fourier transform and MacWilliams identities ( pdf ). 4: Generating characters and finite Frobenius rings ( pdf ). 5: Self-duality for linear codes over modules ( pdf ). 6: MacWilliams extension theorem ( pdf ). 7. Converse of the MacWilliams extension theorem ( pdf ). 8. MacWilliams extension theorem for other weights ( pdf ). 9. Extension theorem for Lee and Euclidean weights ( pdf ). 10. Using monoid algebras ( pdf ). Additional research lectures: 1. Isometry groups of additive codes over finite fields ( pdf ). 2. The extension problem for general weights ( pdf ). 3. Simplicial complexes arising from linear codes ( pdf ).

Homogeneous weight enumerators. Slides for my talk for the conference NonCommutative Rings and their Applications, VII, Lens, France, July 5, 2021. ( pdf )

Weights on Z/mZ and the MacWilliams identities. Slides for my talk in the special session on Finite Fields and Applications, Mathematical Congress of the Americas, Buenos Aires, Argentina, July 20, 2021. ( pdf )

Failures of the MacWilliams identities. Slides for my talk at the BIRS-CMO hybrid workshop Algebraic Methods in Coding Theory and Communication, Oaxaca, Mexico, April 29, 2022. ( pdf )

Linear codes over finite Frobenius rings. Slides for my talk for the online International Conference on Noncommutative Algebra and its Applications, Tehran, Iran, May 9, 2022. ( pdf )

Arithmetic progressions of constant p-adic weight, 2001. ( pdf )

The chain rule for matrix exponential functions, College Math J. 35 (2004), 220-222. ( pdf )

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