Timeline for Some questions on a paper of Baumslag and Solitar
Current License: CC BY-SA 4.0
4 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| May 20, 2021 at 21:28 | vote | accept | user101010 | ||
| May 20, 2021 at 16:03 | comment | added | Carl-Fredrik Nyberg Brodda | @HJRW Yes, that’s a nice compact way of writing the argument in this case! | |
| May 20, 2021 at 15:00 | comment | added | HJRW | The proof using normal forms for HNN extenions is two lines. The given presentation exhibits $BS(2,3)$ as an HNN extension of $\mathbb{Z}\cong \langle b\rangle$, with stable letter $a$ conjugating $\langle b^2\rangle$ to $\langle b^3\rangle$. The word $W=b^{-1}a^{-1}bab^{-1}a^{-1}bab^{-1}$ doesn't contain any pinches $a^{-1}b^{2n}a$ or $ab^{3n}a^{-1}$, so is in normal form and hence non-trivial. | |
| May 19, 2021 at 16:00 | history | answered | Carl-Fredrik Nyberg Brodda | CC BY-SA 4.0 |