Function: concat
Section: linear_algebra
C-Name: concat
Prototype: GDG
Help: concat(x,{y}): concatenation of x and y, which can be scalars, vectors
 or matrices, or lists (in this last case, both x and y have to be lists). If
 y is omitted, x has to be a list or row vector and its elements are
 concatenated
Description: 
 (mp,mp):vec           concat($1, $2)
 (vec,mp):vec          concat($1, $2)
 (mp,vec):vec          concat($1, $2)
 (vec,vec):vec         concat($1, $2)
 (genstr,gen):genstr   concat($1, $2)
 (gen,genstr):genstr   concat($1, $2)
 (gen,?gen):gen        concat($1, $2)

