On the Operator-valued $\mu$-cosine functions

Bouikhalene Belaid, Elqorachi Elhoucien

Let $(G,+)$ be a topological abelian group with a neutral element $e$ and let $\mu :G⟶\mathbb{C}$ be a continuous character of $G$. Let $(\mathcal{H}, \langle \cdot,\cd…