TY - JOUR T1 - Matematické nástroje A1 - Vrábel, Peter JA - Obzory matematiky, fyziky a informatiky Y1 - 2009 VL - 38 IS - 2 SP - 11 EP - 15 SN - 1335-4981 N2 - A semi-invariant is the quantity which is changed monotonically and gains only finite values. Semi-invariants are often used in the analysis of evolving systems to show that certain final configurations must occur. Every investigated object of a problem is assigned some value of quantity and is defined a suitable operation on the set of objects. We concentrate on the least"or the greatest value of semi-invariant and we the problem solve by its means. ER - |