Abstract
We introduce a quadratic form arising from the Cartan matrix of a block of a finite group. By invoking Brauer’s notion of basic sets, we exploit some properties of the quadratic form with will lead to restriction on the number of characters of the block. We also discuss a question about the indecomposability of Cartan matrices.
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Sambale, B. (2014). Quadratic Forms. In: Blocks of Finite Groups and Their Invariants. Lecture Notes in Mathematics, vol 2127. Springer, Cham. https://doi.org/10.1007/978-3-319-12006-5_3
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DOI: https://doi.org/10.1007/978-3-319-12006-5_3
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