There is a lot going on here, in the orchestra's last subscription concerts of the season. The Philharmonic finishes its Beethoven festival, built around the piano concertos, featuring the mighty "Emperor," with Yefim Bronfman as soloist and Alan Gilbert conducting. At the same time, as the orchestra's concertmaster of 34 years, Glenn Dicterow, takes his leave, the Philharmonic pays tribute, featuring him in Beethoven's Triple Concerto, with the principal cellist, Carter Brey, and with Mr. Bronfman as pianist.