Gidon Kremer, like Jordi Savall, is a performer whose gifts go far beyond simple mastery of his instrument. He creates an entire world — a vast repertory tilted toward the present; a style of performance that is at once engagingly casual and ferociously intense; programs that unfold like pages of a cryptic novel. The luminous Latvian is coming to Carnegie this week and the next. On Friday, he appears with the Baltimore Symphony, under Yuri Temirkanov, to play Giya Kancheli's Lonesome and Shostakovich's sublimely dark First Violin Concerto. Then, next Tuesday, he and his Kremerata ensemble present a new piece by Alexander Wustin and two more works of Shostakovich: the Viola Sonata, which the composer finished literally on his deathbed, and the Fifteenth Symphony, in an extraordinarily effective arrangement for piano trio and percussion. As I wrote last year on the blog, I heard Kremer play the "chamber Fifteenth" at the Lockenhaus Festival in 1995, and it was, as Merle Haggard sang last night, unforgettable.