The classical Hennessy-Milner theorem says that two states of an image-finite transition system are bisimilar if and only if they satisfy the same formulas in a certain modal logic. In this paper we study this type of result in a general context. moving from transition systems to coalgebras and from bisimilarity to coinductive predicates. We formulate when a logic fully characterises ... https://www.roneverhart.com/Brach-s-Natural-Sources-Candy-Corn-10-Ounce-Bag/