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Two-dimensional tame and maximal orders of finite representation type. (English) Zbl 0677.16002

Mem. Am. Math. Soc. 408, 72 p. (1989).
Let \(\Lambda\) be an algebra over the power series ring \(T=k[[x,y]]\), \(k\) being algebraically closed with \(\operatorname{char} k = 0\), and \(\Lambda\) finitely generated and free as a \(T\)-module. \(\Lambda\) is said to be representation-finite if the category of finitely generated reflexive \(\Lambda\)-modules has a finite number of indecomposables. The representation-finite algebras \(\Lambda\) are characterized in terms of their Auslander-Reiten quivers. If \(\Lambda\) is representation-finite and indecomposable, then \(\Lambda\) is a tame order in a simple algebra. The Grothendieck group \(G\) of the Auslander-Reiten quiver of \(\Lambda\) is defined, and it is proved that the length of a maximal chain of tame overorders of \(\Lambda\) is just the rank of \(G\). Thus, a criterion for maximal orders \(\Lambda\) is derived, and in particular, this yields a new proof of M. Artin’s classification of representation-finite maximal orders in division rings [Invent. Math. 84, 195–222 (1986; Zbl 0591.16002); Manuscr. Math. 58, 445–471 (1987; Zbl 0625.16005)].

MSC:

16H05 Separable algebras (e.g., quaternion algebras, Azumaya algebras, etc.)
16Gxx Representation theory of associative rings and algebras
16E20 Grothendieck groups, \(K\)-theory, etc.
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