|  |  D.14.1.20 arrIsEssential Procedure from libraryarr.lib(see  arr_lib).
 
Example:Usage:
arrIsEssential(A); arrangement A;
Return:
boolean: 1 if arr is essential, i.e. rank of maximal element of
poset is dimension
Note:
A has to be non-empty.
 See also:
 arrCone;
 arrDecone;
 arrEssentialize;
 arrIsEssential;
 arrRestrict.|  | LIB "arr.lib";
ring S = 0,(x,y,z),lp;
arr A = ideal(x,y,z);
arr B = ideal(x+y+z,x,y+z);
arrIsEssential(A);
==> 1
arrIsEssential(B);
==> 0
 | 
 
 |