Preface to the Special Issue in Memory of Prof. Jiequan Li

On May 14, 2023, the community of computational and applied mathematics lost an exceptional scholar and cherished friend, Professor Jiequan Li. His sudden passing left us with both a profound sense of loss and a deep appreciation of his intellectual legacy. To honor his memory and extraordinary contributions, this special issue of Communications in Computational Physics has been dedicated to him. The collection has been carefully assembled by his friends and collaborators, and it reflects both the breadth of his influence and the vitality of the field he helped shape.