Kerodon

$\Newextarrow{\xRightarrow}{5,5}{0x21D2}$ $\newcommand\empty{}$
$\Newextarrow{\xhookrightarrow}{10,10}{0x21AA}$

Remark 8.5.9.2. The Thompson groupoid $\mathrm{Dy}$ contains exactly two isomorphism classes:

  • The isomorphism class of the degenerate interval $[0,0] = \{ 0 \} $, whose automorphism group is the trivial group.

  • The isomorphism class of the unit interval $[0,1]$, whose automorphism group is the Thompson group $\operatorname{Aut}_{ \mathrm{Dy} }( [0,1] )$ of Definition 8.5.7.12.