Automorphisms of a 3-dimensional handlebody
Automorphisms of a 3-dimensional handlebody
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3 维手柄的自同构
DOI:
10.1007/bf02992786
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发表时间:
1964
期刊:
影响因子:
--
通讯作者:
H. B. Griffiths
中科院分区:
文献类型:
--
作者:
H. B. Griffiths
By a 3-dimensional handlebody T~, we mean a solid ball with n solid handles. Various simple homeomorphs of T~ can be constructed in Euclidean space R 3, and these reveal certain symmetries of Tn. The more obvious ones of these are studied in this paper, and we compute their effects on the fundamental groups: h (T~),: h (8 T~) of T~ and its boundary surface~ T~. Some of them induce the identity on zr 1 (T~) but not on zrl (~ T~), and while we do not know to what extent our list of these is complete, we obtain (Th. 10. 1) a necessary and sufficient condition for an automorphism of: rl (OT~) to be induced by a topological automorphism of T~. Now, a classical result of NIELSEN [3] states that every automorphism of zh (OT~) is induced by an automorphism of O Tn, while of course the homology analogue for HI (~ Tn) is false, since intersection numbers must be preserved. We use some of the symmetries of T~, mentioned above, to prove corresponding results (3.1, 3.3) for T~, namely that every automorphism of: r1 (T~), or of HI (T,~), is induced by an automorphism of T~; we simply show that all the,, Tietze transformations'(which generate the automorphism group of zrl (T~)) are induced by these symmetries.After a manuscript of this work was completed, there appeared the paper [5] of ZIESC~ O, in which our Theorem 3.1 (about: h (T~)) is proved by different methods (op. cit. p. 238, Satz 1). We have used one result from that paper to simplify our proof of Th. 10.1 (mentioned above).