Hcfyk

< 214 > 212 | 213 | 214 | 215 | 216 Kategoriar Fann ikkje kategorien 214 214 i andre kalendrar Gregoriansk kalender 214 CCXIV Ab urbe condita 967 Armensk kalender I/T Kinesisk kalender 2910 – 2911 ?巳 – 甲午 Etiopisk kalender 206 – 207 Jødisk kalender 3974 – 3975 Iransk kalender 408 BP – 407 BP Islamsk kalender 421 BH – 420 BH Hindukalendrar - Vikram Samvat 269 – 270 - Shaka Samvat 136 – 137 - Kali Yuga 3315 – 3316 Hendingar | Fødde | Døde | <<   200-talet   >> << 200 | 201 | 202 | 203 | 204 | 205 | 206 | 207 | 208 | 209 | 210 | 211 | 212 | 213 | 214 | 215 | 216 | 217 | 218 | 219 | 220 | 221 | 222 | 223 | 224 | 225 | 226 | 227 | 228 | 229 | 230 | 231 | 232 | 233 | 234 | 235 | 236 | 237 | 238 | 239 | 240 | 241 | 242 | 243 | 244 | 245 | 246 | 247 | 248 | 249 | 250 | 251 | 252 | 253 | 254 | 255 | 256 | 257 | 258 |...

4 1 $begingroup$ Let $Gamma_{g,b}^m$ denote the mapping class group of a genus $g$ surface with $b$ non-permutable parametrised boundary curves and $m$ permutable punctures. It is clear that in general, presentations for these groups are hard. I only need for the general case a set of generators (I want to show that two morphisms $varphi,psi:Gammato G$ are equal and I want to check this on the generators). Partial answers are the following: If $b,m=0$ (so we have a closed surface), then the group is generated by Dehn twists which can be easily drawn on the surface. If $g,m=0$ , we can declare one boundary curve as “outer” and the group is generated by Dehn twists along the inner boundary curves and the pure braid generators $alpha_{ij}$ . From Farb–Margalit, I know that there are always finitely many ...