For Rewriting Systems
نویسندگان
چکیده
A finite rewriting system is presented that does not satisfy the homotopical finiteness condition FDT, although it satisfies the homological finiteness condition FHT. This system is obtained from a group G and a finitely generated subgroup H of G through a monoid extension that is almost an HNN-extension. The FHT property of the extension is closely related to the FP2 property for the subgroup H, while the FDT property of the extension is related to the finite presentability of H. The example system separating the FDT property from the FHT property is then obtained by applying this construction to an example group considered by Bestvina and Brady (1997).
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