Any fantasy you can think of has multiple dimensions to it; this is especially true in Vijay Iyer’s Bridgetower Phantasy, which premiered in Philadelphia performed by violinist Jennifer Koh and pianist Shai Wosner as part of the Philadelphia Chamber Music Society’s recital season. The March 21 concert at the Kimmel Center’s Perelman Theater featuring the new Iyer work was bookended by two Beethoven violin sonatas, including the Kreutzer sonata. Iyer’s piece is titled after the African violinist to whom Beethoven dedicated his Kreutzer sonata, suggesting that Iyer sees this work as a response and a companion piece to Beethoven’s sonata. These historical and musical resonances made for a compelling program that brought together old and new.