Complex sentence: The Carmen Variations are a set of variations composed and preformed by the russian pianist Vladimir Horowitz (1903-1989), of Horowitz's many transcriptions the variations were the only to remain in his repertoire throughout his career.
Split into simpler sentences: The Carmen Variations are a set of variations composed and performed by the Russian pianist Vladimir Horowitz (1903-1989). Of Horowitz's many transcriptions, the variations were the only ones to remain in his repertoire throughout his career.