If history has taught us anything, it’s that merging of classical and jazz instincts can be a tricky chemistry experiment, prone to explosions and noble failures. Pianist Uri Caine’s recent adventures-mixing music of Mahler with an essentially jazz context-work much better than most, in part because the linguistic rules of conduct somehow remain clear, even as they break molds. He has chosen themes from Mahler, from his Symphonies No. 1, 2, and 5, logically focusing on the pre-modernist composer’s song-like materials, borrowed from or emulating folk traditions. Caine’s compact but colorful chamber ensemble, which includes trumpeter Ralph Alessi and violinist Mark Feldman in the classical crossover corner, the alto saxist-deserving-greater-recognition Dave Binney, drummer Jim Black, bassist Michael Formanek and DJ Olive on turntables and live electronics, surround his piano foundation in a happy swirl of sound, tuneful propriety and fervent improv. They recorded this two-CD set live at the Gustav Mahler Festival, and one can only imagine how it went over with diehard Mahlerians, but it sure sounds good to the ears of listeners still holding out hope for the eclectic ideal. It’s still true: jazz is a bold and broad enough tradition to allow for the integration of idioms normally kept in their separate corners by cultural and social factors.