**porism** — /pöˈ or pōˈri zm/ noun 1. In ancient Greek geometry, a corollary 2. Also a kind of proposition intermediate between a problem and a theorem, according to some a proposition affirming the possibility of finding such conditions as will render a… … Useful english dictionary

**porism** — [pō′riz΄əm, pôr′iz΄əm] n. 〚ME porysme < ML porisma < Gr, lit., a thing brought < porizein, to bring < poros, passage: see PORE2〛 Ancient Math. a geometrical proposition variously defined, as a) a proposition deduced from some other demonstrated… … Universalium

**porism** — [pō′riz΄əm, pôr′iz΄əm] n. [ME porysme < ML porisma < Gr, lit., a thing brought < porizein, to bring < poros, passage: see PORE2] Ancient Math. a geometrical proposition variously defined, as a) a proposition deduced from some other… … English World dictionary

**Porism** — The subject of porisms is perplexed by the multitude of different views which have been held by geometers as to what a porism really was and is.The treatise which has given rise to the controversies on this subject is the Porisms of Euclid, the… … Wikipedia

**porism** — n. geometric proposition that it is possible, in certain conditions, for a problem to have any number of solutions … Dictionary of difficult words

**Poncelet's porism** — In geometry, Poncelet s porism, named after French engineer and mathematician Jean Victor Poncelet, states the following: Let C and D be two plane conics. If it is possible to find, for a given n > 2, one n sided polygon which is simultaneously… … Wikipedia

**Steiner chain** — In geometry, a Steiner chain is a set of n circles, all of which are tangent to two given non intersecting circles (blue and red in Figure 1), where n is finite and each circle in the chain is tangent to the previous and next circles in the chain … Wikipedia

**Poristic** — Po*ris tic, Poristical Po*ris tic*al, a. [Gr. ? for providing, ? provided.] Of or pertaining to a porism; of the nature of a porism. [1913 Webster] … The Collaborative International Dictionary of English

**Poristical** — Poristic Po*ris tic, Poristical Po*ris tic*al, a. [Gr. ? for providing, ? provided.] Of or pertaining to a porism; of the nature of a porism. [1913 Webster] … The Collaborative International Dictionary of English

**Ptolemy's theorem** — In mathematics, Ptolemy s theorem is a relation in Euclidean geometry between the four sides and two diagonals or chords of a cyclic quadrilateral. The theorem is named after the Greek astronomer and mathematician Ptolemy (Claudius Ptolemaeus).If … Wikipedia