The Department of Physics and Astronomy is hosting an invitation-only mini-symposium to celebrate the 90th Birthday of Wolfgang J. Choyke, his long career of research on silicon carbide and other fields, and the importance of Pittsburgh in the development of silicon carbide as a semiconductor for important current and future applications. The symposium program is available at the website: https://indico.cern.ch/e/Choyke90 If you have questions, please contact Bob Devaty (devaty@pitt.edu) or Michele Slogan (slogan@pitt.edu).