Combinatorial enumeration is a subfield of enumeration that deals with the counting of objects whose symmetries do not exist or, if they exist, are combinatorial in nature. See combinatorics. suvodip ... Square with symmetry group D4 Symmetry is a characteristic of geometrical shapes, equations, and other objects; we say that such an object is symmetric with respect to a given operation if this operation, when applied to the object, does not appear to change it. ... Dividing a circle into areas. ...
Combinatorics is a branch of mathematics that studies finite collections of objects that satisfy specified criteria.
In particular, it is concerned with "counting" the objects in those collections (enumerativecombinatorics) and with deciding whether certain "optimal" objects exist (extremal combinatorics) and which "algebraic" structures these objects have (algebraic combinatorics).
Combinatorics came to prominence after the publication of the celebrated Combinatory Analysis by Percy Alexander MacMahon in 1915.
It studies finite collections of objects that satisfy certain criteria, and is in particular concerned with "counting" the objects in those collections (enumerativecombinatorics) and with deciding whether certain "optimal" objects exist (extremal combinatorics).
One of the most prominent combinatorialists of recent times was Gian-Carlo Rota, who helped formalize the subject beginning in the 1960s.
EnumerativeCombinatorics, Volumes 1 and 2 (http://www-math.mit.edu/~rstan/ec/), Richard P. Stanley, Cambridge University Press, 1997 and 1999, ISBN 0-521-55309-1n