Clifford algebras and Littlewood-Richardson coefficients

Calvert, Kieran and Grizelj, Karmen and Krutov, Andrey and Pandžić, Pavle (2024) Clifford algebras and Littlewood-Richardson coefficients. Other. Arxiv.

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Abstract

We show how to use Clifford algebra techniques to describe the de Rham cohomology ring of equal rank compact symmetric spaces $G/K$. In particular, for $G/K=U(n)/U(k)\times U(n-k)$, we obtain a new way of multiplying Schur polynomials, i.e., computing the Littlewood-Richardson coefficients. The corresponding multiplication on the Clifford algebra side is, in a convenient basis given by projections of the spin module, simply the componentwise multiplication of vectors in $\mathbb{C}^N$, also known as the Hadamard product.