Timeline for Words which are not inverted by any endomorphism
Current License: CC BY-SA 4.0
3 events
| when toggle format | what | by | license | comment | |
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| Sep 15, 2023 at 6:16 | comment | added | ADL | @Shri That case corresponds precisely to $\psi$ being an automorphism (as $u$ is fixed by $\psi^2$, and as it is a test word $\psi^2$ is an automorphism, and hence $\psi$ is an automorphism too by Hopficity of free groups). Different techniques will be needed for $\psi$ an automorphism. [The splitting of "automorphism" vs "non-automorphism" is really common in this area.] | |
| Sep 15, 2023 at 5:35 | comment | added | Shri | Thank you for your answer. But what about when $u$ becomes a test word? | |
| Sep 14, 2023 at 10:38 | history | answered | ADL | CC BY-SA 4.0 |