Anne Teresa De Keersmaeker’s and Jérôme Bel’s 3Abschied is the latest addition to a long and historically well-established series of choreographic works set to music by Gustav Mahler. There are still those, however, who cringe at the idea of dancing to the notes of this revered composer — as Keersmaeker points out in her initial monologue where she recounts her encounter with the conductor supremo Daniel Barenboim.