Theories of categorization have typically focused on the internal structure of categories. This paper is concerned with the external structure of categories. In particular, it is suggested that many categories specify the relational role that is played by category members. To support this claim, the paper distinguishes between traditional feature-based categories, relational categories (which s...

The paper presents cognitive mechanisms and behavioral rules by which a group of distributed autonomous agents may develop a joined shared repertoire of grammatical conventions. The grammar includes an emergent internal meta-level ontology which is exploited for tightening the grammatical constraints. To illustrate the latter, it is shown how a proto-typical form for members of a syntactic cate...

For a given Galois structure on a category C and an eeective descent morphism p : E !B in C we describe the category of so-called weakly split objects over (E; p) in terms of internal actions of the Galois (pre)groupoid of (E; p) with an additional structure. We explain that this generates various known results in categorical Galois theory and in particular two results of M. Barr and R. Diacone...

We develop a theory of categories which are simultaneously (1) indexed over a base category S with finite products, and (2) enriched over an S-indexed monoidal category V . This includes classical enriched categories, indexed and fibered categories, and internal categories as special cases. We then describe the appropriate notion of “limit” for such enriched indexed categories, and show that th...

In this article we study locally compact abelian (LCA) groups from the viewpoint of derived categories, using that their category is quasi-abelian in the sense of J.-P. Schneiders. We define a well-behaved derived Hom-complex with values in the derived category of Hausdorff topological abelian groups. Furthermore we introduce a smallness condition for LCA groups and show that such groups have a...

In this paper a way to have structures with partiality in its internal structure in a categorical approach is presented and, with this, a category of partial graphs Grp is given and partial automata are constructed from Grp. With a simple categorical operation, computations of partial automata are given and can be seen as a part of the structure of partial automata. Keyworks: computation, parti...

Recent theoretical and empirical developments in human category learning have differentiated an analytic, rule-based system of category learning from a nonanalytic system that integrates information across stimulus dimensions. In the present study, the researchers applied this theoretical distinction to pigeons' category learning. Pigeons learned to categorize stimuli varying in the tilt and wi...

The Korean Journal of Internal Medicine has already been valued as an international journal, according to a citation analysis in 2011. Now, 2 years later, I would like to confirm how much the Journal has advanced from the point of view of journal metrics by looking at the impact factor, cites per document (2 years), SCImago Journal Rank (SJR), and the Hirsch index. These were obtained from a va...