On Thursday, April 30, at 8:00p, and Saturday, May 2, at 7:30p at Atlanta Symphony Hall, Music Director Robert Spano leads a concert that opens with the world premiere of Imaginary Numbers, by Atlanta School Composer Michael Gandolfi. Soloists are Atlanta Symphony Principals Elisabeth Koch Tiscione, Laura Ardan, Keith Buncke, and Brice Andrus. The first half of the program ends with the Suite from Igor Stravinsky’s ballet, The Firebird. Jean-Yves Thibaudet is the soloist in Maurice Ravel’s Piano Concerto in G. The program concludes with George Gershwin’s An American in Paris. The First Fridays concert, performed without intermission, takes place on Friday, May 1, at 6:30p, and includes the Stravinsky, Ravel and Gershwin works.