International conference
Combinatorial Methods in Physics and Knot Theory

Vladimir VERSHININ (univ. Montpellier 2): Presentations of generalizations of braids

In his initial paper on braids E. Artin gave a presentation of an arbitrary braid group with two generators, say $\sigma_1$ and $\sigma$, and the following relations:
\begin{cases} \sigma_1 \sigma^i \sigma_1 \sigma^{-i} &= \sigma^i \sigma_1 \sigma^{-i} \sigma_1 \ \ \text{for} \ \ 2 \leq i\leq {n / 2}, \\ \sigma^n &= (\sigma \sigma_1)^{n-1}. \end{cases}
The connection with the canonical generators is given by the formulae:
\sigma = \sigma_1 \sigma_{2} \dots \sigma_{n-1},
\sigma_{i+1} =\sigma^i \sigma_1 \sigma^{-i}, \quad i =1, \dots {n-2}.
We observe analogues of this Artin's presentation for various generalizations of braids. For example, the singular brad monoid $SB_n$ has a presentation with generators $\sigma_1$, $\sigma_1^{-1}$, $\sigma$, $\sigma^{-1}$ and $x_1$ and relations
\begin{cases} \sigma_1 \sigma^i \sigma_1 \sigma^{-i} = \sigma^i \sigma_1 \sigma^{-i} \sigma_1 \ \ \text{for} \ \ 2 \leq i\leq {n / 2}, \\ \sigma^n = (\sigma \sigma_1)^{n-1},\\ x_1\sigma^i\sigma_1\sigma^{-i}= \sigma^i\sigma_1\sigma^{-i} x_1 \ \ \text{for} \ \ i=0, 2 \dots {n - 2}, \\ x_1 \sigma^i x_1 \sigma^{-i} = \sigma^i x_1 \sigma^{-i} x_1 \ \ \text{for} \ \ 2 \leq i\leq {n / 2}, \\ \sigma^n x_1 = x_1\sigma^n,\\ x_1\sigma\sigma_1\sigma^{-1}\sigma_1 = \sigma\sigma_1\sigma^{-1}\sigma_1 \sigma x_1\sigma^{-1}, \\ \sigma_1\sigma_1^{-1}=\sigma_1^{-1}\sigma_1 =1,\\ \sigma\sigma^{-1}=\sigma^{-1}\sigma =1. \end{cases}
The other presentations, as that of J. S. Birman, K. H. Ko and S. J. Lee or Sergiescu graph presentations are also considered.