Train track maps for graphs of groups

Martin Lustig

备注：: This is a completely new article (now 22 pages) with much more detailed statements and proofs, a main theorem that applies also to free products, and with a detailed description of the algorithm in a new section. In the last section an interesting example is given

英文摘要：

We define train track maps for graphs-of-groups $\cal G$ and exhibit the precise conditions under which the fundamental finiteness properties known for classical train track maps extend to this generalization. These finiteness properties are the crucial tool to control the decrease of illegal turns under iteration of the train track map, and they are a principal ingredient in the answer to basic algorithmic questions about automorphisms induced by such train track maps on $π_1 \cal G$.

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