Until about three weeks ago, the entire ensemble had been expecting to give the first concerts ever by an American orchestra in the country as part of this year’s East Asia tour. But Mongolia’s suffering through a severe economic crisis, and all that could be salvaged is a three-day visit by 18 of the Philadelphians. David Patrick Stearns (who’ll be with them) gives a preview of what’ll be happening – and explains why the Mongolians only gave three weeks’ notice that the whole orchestra couldn’t come.