Preface

The 12th edition of the conference GASCom on random and exhaustive generation of combinatorial structures was held in Varese, Italy, on June 13-15th, 2022.The very first edition of the series of conference GASCom took place in Bordeaux in 1994, followed by subsequent editions in Caen (1997), in Bordeaux (1999) and in Siena (2001).Then, starting in 2006, the conference has been held regularly every two years until now (with the only exception of the 2020 edition, due to the Coronavirus pandemic), specifically in Dijon ( 2006), Bibbiena (2008), Montreal (2010), Bordeaux (2012), Bertinoro (2014), Bastia (2016), Athens (2018) and of course Varese (2022).This special issue on Randomness and Combinatorics contains a selection of papers presented at the 2022 conference and additional papers from this area of research.Starting from the common theme of random and exhaustive generation of combinatorial objects, the topics explored in the collected contributions span from all kinds of enumerative, bijective and analytic combinatorics, to algorithmic aspects (such as analysis of algorithms and probabilistic algorithms) and interactions with other areas of mathematics and computer science (such as combinatorics on words and tilings).The selection of papers we have made would not have been possible without the help of several referees, whose invaluable efforts have been fundamental in making all final decisions.We heartfully thank all of them for having made this volume possible.We would like to thank all the participants at GASCom 2022 and the authors of the collected papers, whose precious contributions have been the main ingredients for a successful conference and an equally successful special issue.In particular, we would like to express our gratitude to the three invited speakers Cyril Banderier (LIPN, Paris, France), Paola Bonizzoni (University of Milan-Bicocca, Italy) and Tony Guttmann (