We are pleased to send the first announcement of the 4th international symposium on Riordan Arrays and Related Topics (4RART). The symposium will be held July 17-20, 2017 at Facultad de Ciencias Matemáticas, Universidad Complutense de Madrid, Spain.   We encourage the interested participants to present a 20 minutes contributed talk. Keynote speakers: Froilán Dopico, … Sigue leyendo First announcement of the 4th International Symposium on Riordan Arrays and Related Topics (4RART)