Geodesic
Representations of algebraic groups of type $C_n$ with small weight multiplicities
Zapiski Nauchnykh Seminarov POMI, Problems in the theory of representations of algebras and groups. Part 19, Tome 375 (2010), pp. 140-166 
A. A. Osinovskaya; I. D. Suprunenko. Representations of algebraic groups of type $C_n$ with small weight multiplicities. Zapiski Nauchnykh Seminarov POMI, Problems in the theory of representations of algebras and groups. Part 19, Tome 375 (2010), pp. 140-166. http://geodesic.mathdoc.fr/item/ZNSL_2010_375_a8/
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     title = {Representations of algebraic groups of type $C_n$ with small weight multiplicities},
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     url = {http://geodesic.mathdoc.fr/item/ZNSL_2010_375_a8/}
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Voir la notice du chapitre de livre provenant de la source Math-Net.Ru

We find lower estimates for the maximal weight multiplicities in irreducible representations of algebraic groups of type $C_n$ in characteristic $p\leq7$. If $n\geq8$ and $p\ne2$, then for an irreducible representation such multiplicity is either at least $n-4-[n]_4$, where $[n]_4$ is the residue of $n$ modulo 4, or all weight multiplicities are equal to 1. For $p=2$ the situation is more complicated and for every $n$ and $l$ there exists a class of representations with the maximal weight multiplicity equal to $2^l$. For symplectic groups in characteristic $p>7$ and spinor groups similar results were obtained earlier. Bibl. – 15 titles.

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