What is Special Case?

Legal Definition
In logic, especially as applied in mathematics, concept A is a special case or specialization of concept B precisely if every instance of A is also an instance of B but not vice versa, or equivalently, if B is a generalization of A. A limiting case is a type of special case which is arrived at by taking some aspect of the concept to the extreme of what is permitted in the general case. A degenerate case is a special case which is in some way qualitatively different from almost all of the cases allowed.

Special case examples include the following:

  • All squares are rectangles (but not all rectangles are squares); therefore the square is a special case of the rectangle.
  • Fermat's Last Theorem, that an + bn = cn has no solutions in positive integers with n > 2, is a special case of Beal's conjecture that ax + by = cz has no primitive solutions in positive integers with x, y, and z all greater than 2—​​specifically, the case of x = y = z.
-- Wikipedia
Legal Definition
In English practice. When a trial at nisi prtus appears to the judge to fum on a point of law, the jury may find a general verdict, subject to the opinion of the court above, upon what is termed a "special case" to be made; that is, upon a written statement of all the facts of the case drawn up for the opinion of the court in bane, by the counsel and attorneys on either side, under correction of the judge at nisi prius. The party for whom the general verdict is so given is in such case not entitled to judgment til] the court in banc has decided on the special case; and, according to the result of that decision, the verdict is ultimately entered either for him or his adversary. Brown.
-- Black's Law Dictionary
Legal Definition
Same as Case reserved.
-- Ballentine's Law Dictionary