Regions, extensions, distances, diameters.

Extended simple regions have been the focus of recent developments in philosophical logic, metaphysics, and philosophy of physics. However, only a handful of works provides a rigorous characterization of an extended simple region. In particular, a recent paper in this journal defends a definition based on an extrinsic notion of least distance. Call it the Least Distance proposal. This paper provides the first assessment of it. It argues that Least Distance faces difficulties and drawbacks. The paper then goes on to suggest a different proposal, the Diameter proposal that is able to handle such drawbacks and difficulties. [ABSTRACT FROM AUTHOR]