We refer to articles by Bird [I] and Bird et al. [2] on automorphisms ol' posets. Let P, Q de-ote posets; P x Q is the Cartesian product with the lexicographic order and R&Q that same product with the "reverse" lexicographic order, viz. (p, -1) < (a', 9') iff 4 < q' or q = 4' and p \*f p'. r(P) deno
A note on the automorphisms of maximal orders
β Scribed by M.-A Knus; M Ojanguren
- Publisher
- Elsevier Science
- Year
- 1972
- Tongue
- English
- Weight
- 283 KB
- Volume
- 22
- Category
- Article
- ISSN
- 0021-8693
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π SIMILAR VOLUMES
dedicated to professor helmut wielandt on the occasion of his 90th birthday ## 1. INTRODUCTORY REMARKS Let G be a group and denote by PAut G the group of power automorphisms of G (see [4]). An automorphism of G is called an I-automorphism of G if it maps every infinite subgroup of G onto itself. T
Perfectly orderable graphs were introduced by Chvfital in 1984. Since then, several classes of perfectly orderable graphs have been identified. In this paper, we establish three new results on perfectly orderable graphs. First, we prove that every graph with Dilworth number at most three has a simpl
Given a (finite or infinite) set X, a collection C P(X ) of subsets of X is called a hierarchy if it satisfies the condition ` '' In this note, we characterize maximal hierarchies as set systems that contain the empty set, the full set, and all one-element sets, and in addition satisfy either one of