An assignment-based lower bound for a class of two-machine flow shop problems

We present an assignment-based lower bound that is valid for a wide class of two-machine flow shop problems with a regular additive performance criterion. We provide empirical evidence that this new bound consistently outperforms state-of-the-art lower bounds in two important special cases: F2∥∑CjF2∥∑Cj and F2∥∑TjF2∥∑Tj. Moreover, we illustrate its wide applicability and good performance on two additional problems: F2∥∑Cj and F2∥∑lnCj.