Kawashima's relations for interpolated multiple zeta values

Recently, Yamamoto introduced polynomials in one variable t which interpolates multiple zeta and zeta-star values (t-MZVs for short), provided new prospects on two-one conjecture of Ohno and Zudilin and proved the cyclic sum formula for t-MZVs. In this paper, we establish a generalization of Kawashima's relations (t-Kawashima relations) for t-MZVs. We prove the cyclic sum formula for t-MZVs using a type of derivation operator, together with the t-Kawashima relations.