Abstract:A concrete category $\Bbb K$ is (algebraically) {universal} if any category of algebras has a full embedding into $\Bbb K$, and $\Bbb K$ is {almost universal} if there is a class $\Cal C$ of $\Bbb K$-objects such that all non-constant homomorphisms between them form a universal category. The main result of this paper fully characterizes the finitely generated varieties of $0$-lattices which are almost universal.
Keywords: (algebraically) universal category, finite-to-finite universal category, almost universal category, $0$-lattice, variety of $0$-lattices
AMS Subject Classification: Primary 18B15, 06B20; Secondary 08A35