porism การใช้

A porism is a type of theorem relating to the number of solutions and the conditions on it.
With the mention of the " Porisms " of Euclid we have an account of the relation of porism to theorem and problem.
This is a corollary of Poncelet's porism, which was proved by the French mathematician Jean-Victor Poncelet ( 1788 1867 ).
Porisms often describe a geometrical figure that cannot exist unless a condition is met, but otherwise may exist in infinite number; another example is Poncelet's porism.
Though this definition of a porism appears to be most favoured in England, Simson's view has been most generally accepted abroad, and had the support of Michel Chasles.