Presentations of Feigin-Stoyanovsky's type subspaces of standard modules for affine Lie algebras of type $C_\ell^{(1)}$

Abstract

Feigin-Stoyanovsky's type subspace $W(\Lambda)$ of a standard $\tilde{{\mathfrak g}}$-module $L(\Lambda)$ is a $\tilde{{\mathfrak g}}_1$-submodule of $L(\Lambda)$ generated by the highest-weight vector $v_\Lambda$, where $\tilde{{\mathfrak g}}_1$ is a certain commutative subalgebra of $\tilde{{\mathfrak g}}$. Based on the description of basis of $W(\Lambda)$ for $\tilde{{\mathfrak g}}$ of type $C_\ell^{(1)}$, we give a presentation of this subspace in terms of generators and relations $$W(\Lambda)\simeq U(\tilde{{\mathfrak g}}_1^-)/J.$$