Completely regular semigroup varieties

lt;p>Mario Petrich received his PhD from the University of Washington in 1961 and held positions in many universities across Austria, Canada, France, Germany, Italy, Portugal, Spain, the UK, and the US, including Pennsylvania State University, University of Western Ontario, University of Vienna, University of St Andrews, Simon Fraser University, and University of Montpellier. He was a Founding Editor of Semigroup Forum. Dr. Petrich has published over 260 articles, seven monographs and one Research Note. The principal focus of his work was in the field of semigroup theory.

Norman Reilly received his PhD from Glasgow University in 1965 and has held positions at Glasgow University, Tulane University, and Simon Fraser University. Dr. Reilly has published over 100 articles and two books. He is a long time editor of Semigroup Forum and the International Journal of Algebra and Computation. The focus of his research has been on algebraic systems, including ordered algebraic systems, with a main focus on the theory of semigroups.

lt;p>Fully Invariant Relations.- Kernel and Trace Relations.- Bands.- Polák Theorem.