The minimalist masterpiece. (Whut's minimalism? Why, according to its enemies, it's fascist-consumerist-narcissism. In otherworlds, it's classical music's Rock 'n' Roll. Sayeth the dour serialists: "God indeed does throw dice,/ but never does he ever/ say the same thing twice.") "Dean" Christgau gave it an A minus. Well, one is tempted to hedge a bit with such a reputation on the line. On the other hand . . .