This book gathers a selection of refereed papers presented at the "International Conference on Operations Research OR2015," which was held at the University of Vienna, Austria, September 1-4, 2015.

This book constitutes thoroughly refereed and revised selected papers from the 7th International Symposium on Combinatorial Optimization, ISCO 2022, which was held online during May 18–20, 2022.The 24 full papers included in this book were carefully reviewed and selected from 50 submissions. They were organized in topical sections as follows: Polyhedra and algorithms; polyhedra and combinatorics; non-linear optimization; game theory; graphs and trees; cutting and packing; applications; and approximation algorithms.