@ @Y@ @óïbÿa@‡ÉÜa@ú†bjà@ @ (n )B f :A→B .n .(m )A .n ×n × ×n = nm [Correspondence Principle] A B BA .A BA .A = B B A : ) f :A→B () m (1 0 (1 0 ) .m a1a2 … am m .2 × 2 × × 2 = 2m .ai .m A () A