FOREWORD

Discrete mathematics has been applied to various areas in computer science and engineering and proved important as their foundation.This special section is the thirty-fourth in a series that appears in IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences.It aims to review the latest progress in discrete mathematics and its applications and contribute to further development in the research field.The 2025 special section includes 11 full papers and 1 letter paper, which cover various topics in discrete mathematics, including algorithms and data structures, cryptography and information security, and nonlinear problems.These papers were selected from 19 submissions with careful reviews by technical experts.We would like to express our sincere appreciation to all the authors for their valuable contributions.We also thank the anonymous reviewers for their voluntary work.