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Code algebras which are axial algebras and their ℤ2-gradings

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Abstract

A code algebra AC is a non-associative commutative algebra defined via a binary linear code C. We study certain idempotents in code algebras, which we call small idempotents, that are determined by a single nonzero codeword. For a general code C, we show that small idempotents are primitive and semisimple and we calculate their fusion law. If C is a projective code generated by a conjugacy class of codewords, we show that AC is generated by small idempotents and so is, in fact, an axial algebra. Furthermore, we classify when the fusion law is ℤ2-graded. In doing so, we exhibit an infinite family of ℤ2×2-graded axial algebras—these are the first known examples of axial algebras with a non-trivial grading other than a ℤ2-grading.

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References

  1. A. Castillo-Ramirez, J. McInroy and F. Rehren, Code algebras, axial algebras and VOAs, Journal of Algebra 518 (2019), 146–176.

    Article  MathSciNet  Google Scholar 

  2. J. I. Hall, F. Rehren and S. Shpectorov, Universal axial algebras and a theorem of Sakuma, Journal of Algebra 421 (2015), 394–424.

    Article  MathSciNet  Google Scholar 

  3. J. I. Hall, F. Rehren and S. Shpectorov, Primitive axial algebras of Jordan type, Journal of Algebra 437 (2015), 79–115.

    Article  MathSciNet  Google Scholar 

  4. J. I. Hall, Y. Segev and S. Shpectorov, Miyamoto involutions in axial algebras of Jordan type half, Israel Journal of Mathematics 223 (2018), 261–308.

    Article  MathSciNet  Google Scholar 

  5. A. A. Ivanov, The Monster Group and Majorana Involutions, Cambridge Tracts in Mathematics, Vol. 176, Cambridge University Press, Cambridge, 2009.

  6. S. M. S. Khasraw, J. McInroy and S. Shpectorov, On the structure of axial algebras, https://doi.org/abs/1809.10132.

  7. C. H. Lam and H. Yamauchi, Binary codes and the classification of holomorphic framed vertex operator algebras, in Combinatorial Representation Theory and Related Topics, RIMS Kôkyûroku Bessatsu, Vol. B8, Research Institute for Mathematical Sciences, Kyoto, 2008, pp. 131–150.

    MathSciNet  MATH  Google Scholar 

  8. T. De Medts and M. Van Couwenberghe, Modules over axial algebras, Algebras and Representation Theorey, https://doi.org/10.1007/s10468-018-9844-y.

  9. T. De Medts and F. Rehren, Jordan algebras and 3-transposition groups, Journal of Algebra 478 (2017), 318–340.

    Google Scholar 

  10. F. Rehren, Generalised dihedral subalgebras from the Monster, Transactions of the American Mathematical Society 369 (2017), 6953–6986.

    MathSciNet  Google Scholar 

  11. F. Rehren, Linear idempotents inMatsuo algebras, Indiana UniversityMathematics Journal 65 (2016), 1713–1733.

    MathSciNet  Google Scholar 

  12. Y. Segev, Half-axes in power associative algebras, Journal of Algebra 510 (2018), 1–23.

    Article  MathSciNet  Google Scholar 

Download references

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Correspondence to Alonso Castillo-Ramirez.

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Castillo-Ramirez, A., McInroy, J. Code algebras which are axial algebras and their ℤ2-gradings. Isr. J. Math. 233, 401–438 (2019). https://doi.org/10.1007/s11856-019-1911-5

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  • DOI: https://doi.org/10.1007/s11856-019-1911-5

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