Christiane Tammer, an internationally recognized mathematician from Germany, will give the next presentation in the Northern Michigan University International Speaker Series. Tammer works at the Martin Luther University Institute of Mathematics in Halle-Wittenberg, Germany, where her research interests are in applied mathematics. She will discuss “Algorithms for Multi-Criteria Location and Routing Problems” from 4-5:30 p.m. Wednesday, Oct. 15, in Mead Auditorium in the West Science Building. The public is invited to attend free of charge. The event is sponsored by the NMU mathematics and computer science department, the provost office and the office of international programs.