Hi It's Me From The Thing Ha Ha

I'm currently at the library, and a guy just sat down at my same table and I know him from yoga, he is Shervin and he's taken my class before and I recognize him but don't know if I should say something because what if he doesn't recognize me and then it will be creepy but also if I don't say something it's rude and maybe I'll see him at yoga later and we will have that terrible moment where we realize it was each other who we saw at the library but can't decide whether to acknowledge it or not what to do??