Integration of constraint programming artificial intelligence and operations research : 20th international conference CPAIOR 2023 Nice France May 29 June 1 2023 : proceedings This book constitutes the proceedings of the 20th International Conference on the Integration of Constraint Programming Artificial Intelligence and Operations Research CPAIOR 2022 held in Nice France during May 29 June 1 2023. The 26 full papers and the 6 short papers presented in this book were carefully reviewed and selected from a total of 71 submissions. The content of the papers present new techniques or new applications and provide an opportunity for researchers in one area to learn about techniques in the others. Besides they give researchers the opportunity to show how the integration of techniques from different fields can lead to interesting results on large and complex problems