Q: How to put two cellist Artistic Directors - Hiro Matsuo and Ted Nelson - to work on the same night? A: An entire concert featuring cellists in duos with other people: aptly titled Cello Plus. The evening features music for cello “plus one,” (who *just might* be Stefani Matsuo and Ixi Chen) in world premieres by Pierre Jalbert and Michael Ippolito.  Additional plus-ones include artistic directors Henrik Heide and Michael Culligan--who are no less important even if they aren’t married to Ted or Hiro.