Let G = (G, x, less than or equal to) be a linearly ordered, commutati
ve group and u+v = max(u, v) for all u, v epsilon G. Extend +, x in th
e usual way on matrices over G. An m x n matrix A is said to have stro
ngly linearly independent (SLI) columns, if for some b the system of e
quations Axx = b has a unique solution. If, moreover, m = n then A is
said to be strongly regular (SR). This paper is a survey of results co
ncerning SLI and SR with emphasis on computational complexity. We pres
ent also a similar theory developed for a structure based on a linearl
y ordered set where + is maximum and x is minimum.