Sir András Schiff praised the “astonishing clarity, purity, and maturity” of pianist Schaghajegh Nosrati. She makes her Carnegie Hall debut in a performance of works by Bach, Haydn, and Alkan—composers with whom she is closely associated. Bach’s Partita No. 6 is a colossus of complex counterpoint (music with two or more simultaneous melodies), technical daring, and deep emotion. Alkan’s magnificent and rarely performed Concerto for Solo Piano, a tour-de-force showpiece that has become infamous for its technical and musical challenges, brings this recital to a breathtaking close.