What is the fine-grained topic of the following text: For any of you lucky enough to be at the Arlene Schnitzer Concert Hall last Monday night, October 8, 2018, well, you know how special it was seeing Gregory Alan Isakov perform with the Portland Symphony. Only return the topic.
Gregory Alan Isakov's performance with the Portland Symphony at the Arlene Schnitzer Concert Hall on October 8, 2018.