I am writing my master thesis about the following article:
https://arxiv.org/abs/2002.10278
On page 14, Fujiwara and Sela give a proof that hyperbolic groups are Hopfian. They say that de la Harpe ("Topics in geometric group theory" (version of 2000)) pointed out that the existence odf a minimum for the set of exponential growth rates gives an alternative proof for the Hopf property of hyperbolic groups.
I want to cite the original source for that, so the book of de la Harpe. I looked into it but did not find the statement (or a similar statement) in his book. In their references, Fujiwara and Sela say that they used chapter VI and pp. 310 of this book. I looked there (and also at other plausible places in the book, e.g. the chapter about hyperbolic groups) but I dont know where the above statemend is there.
Does anybody of you have the book of de la Harpe and knows to what Fujiwara and Sela refer to exactly?