The Annual Iranian Mathematics Conference (AIMC) has been held since 1970. It is the oldest Iranian scientific gathering which takes place regularly each year at one of Iranian universities. The 51th annual Iranian mathematics conference was held at University of Kashan. The 51th AIMC was be held virtually (because of the Covid-19 virus) at University of Kashan in Kashan (one of the most beautiful and historical city of Iran) from February 16 until February 19, 2021 .
The Iranian Mathematical Society and University of Kashan have jointly sponsored the 51th AIMC. This conference is an international conference and includes Keynote speakers, Invited speakers, Presentations of contributed research papers, and Poster presentations. It is our pleasure to publish some of selected papers in the special issue of The Advanced Studies: Euro-Tbilisi Mathematical journal. The chair of scientific committee of AIMC51 was Alireza Ashrafi who died in a car accident on the way home in Kashan on 9 January 2023, when a drunk driver was driving in the wrong direction. This unfortunate incident shocked all of us. He was completing this issue when this happened and I considered it my duty to complete this issue to may Alireza’s soul rest in peace and not worry about these articles. I hope Alireza’s soul is happy.
In the end, I would like to thank Professor Inassridze Editor-in-Chief of ASETMJ for friendly cooperation, all my friends and colleagues whose helped in the preparation of this issue, especially the student of Alireza, Kurosh Mavaddat Nezhaad.
Lead guest editor: Saeid Alikhani
Guest editors: Alain Bretto, Tomislav Doslic, Hamid Mousavi, and Abdolrahman Razani.