A dihedron is a degenerate Platonic solid with only two (identical) faces, which may be any regular polygon (including possibly the degenerate bigon, which would make the dihedron very degenerate!)
ADE classification and McKay correspondence
Felix Klein, chapter I.4 of Vorlesungen über das Ikosaeder und die Auflösung der Gleichungen vom fünften Grade, 1884, translated as Lectures on the Icosahedron and the Resolution of Equations of Degree Five by George Morrice 1888, online version
Wikipedia, Dihedron
Last revised on August 29, 2019 at 04:43:27. See the history of this page for a list of all contributions to it.