Mathematical tools ‒ semi-invariants. (Matematické nástroje.) (Slovak. English summary)

Obz. mat. fyz. inform. 38, No. 2, 11-15 (2009).

Summary: 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 to some quantity value and is defined as a suitable operation on the set of objects. We concentrate on the least or the largest value of the semi-invariant and we solve the problem by its means.