Nathaniel Pappas
Published 2013-09-15, updated 2014-07-17Version 2
We calculate the rank gradient and p-gradient of free products, free products with amalgamation over an amenable subgroup, and HNN extensions with an amenable associated subgroup. The notion of cost is used to compute the rank gradient of amalgamated free products and HNN extensions. For the p-gradient the Kurosh subgroup theorems for amalgamated free products and HNN extensions will be used.
Comments: Cost of restricted action result has been strengthened. Proofs of main results have been shortened and altered. Article length has been shortened
Stability of amalgamated free products and HNN extensions
Examples of amalgamated free products and coupling rigidity
C$^*$-simple groups: amalgamated free products, HNN extensions, and fundamental groups of 3-manifolds
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