Difference between revisions of "Classification by p-group"
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We use the following notation for Morita equivalence classes of blocks of finite groups with respect to an algebraically closed field k.    | We use the following notation for Morita equivalence classes of blocks of finite groups with respect to an algebraically closed field k.    | ||
| − | M(x,y,z) is a class consisting of blocks with defect groups of order x, with a representative having defect group SmallGroup(x,y) in GAP/MAGMA labelling. It is the z-th such class.    | + | <math>M(x,y,z)</math> is a class consisting of blocks with defect groups of order x, with a representative having defect group SmallGroup(x,y) in GAP/MAGMA labelling. It is the z-th such class.    | 
| − | Note that it is not known that the isomorphism class of a defect group is a Morita invariant, so it could be that <math>M(x,y1,z1)=M(x,y2,z2)<  | + | Note that it is not known that the isomorphism class of a defect group is a Morita invariant, so it could be that <math>M(x,y1,z1)=M(x,y2,z2)</math> for some <math>(y1,z1) \neq (y2,z2)</math>.  | 
Also, at present there is no known example of a k-Morita equivalence class of blocks which splits into more than one Morita equivalence class with respect to a complete discrete valuation ring. If such an example arises, then we will bring in more notation for classes with respect to the d.v.r.  | Also, at present there is no known example of a k-Morita equivalence class of blocks which splits into more than one Morita equivalence class with respect to a complete discrete valuation ring. If such an example arises, then we will bring in more notation for classes with respect to the d.v.r.  | ||
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{| class="wikitable"  | {| class="wikitable"  | ||
|-  | |-  | ||
| − | ! scope="col"| |D|  | + | ! scope="col"| <math>|D|</math>  | 
! scope="col"| SmallGroup    | ! scope="col"| SmallGroup    | ||
! scope="col"| Isotype  | ! scope="col"| Isotype  | ||
| − | ! scope="col"| k-  | + | ! scope="col"| Known <math>k</math>-(<math>\mathcal{O}</math>-)classes  | 
| − | + | ! scope="col"| Complete (w.r.t.)?  | |
| − | ! scope="col"| Complete w.r.t.   | + | ! scope="col"| Derived equiv classes (w.r.t)?  | 
| − | ! scope="col"|   | + | ! scope="col"| References  | 
| − | ! scope="col"|   | ||
! scope="col"| Notes  | ! scope="col"| Notes  | ||
|-  | |-  | ||
| Line 24: | Line 23: | ||
| 1    | | 1    | ||
| 1    | | 1    | ||
| − | | 1    | + | | 1(1)   | 
| − | + | | <math>\mathcal{O}</math>  | |
| − | |   | + | | <math>\mathcal{O}</math>  | 
| − | |||
| − | |   | ||
|    | |    | ||
| + | |||
|-  | |-  | ||
| 2    | | 2    | ||
| 1    | | 1    | ||
| − | | C_2    | + | | <math>C_2</math>   | 
| − | | 1    | + | | 1(1)   | 
| − | + | | <math>\mathcal{O}</math>  | |
| − | |   | + | | <math>\mathcal{O}</math>  | 
| − | |||
| − | |   | ||
|    | |    | ||
| + | |||
|-  | |-  | ||
| 3  | | 3  | ||
| 1  | | 1  | ||
| − | | C_3  | + | | <math>C_3</math>  | 
| − | | 2  | + | | 2(2)  | 
| − | + | | <math>\mathcal{O}</math>  | |
| − | |   | + | | <math>\mathcal{O}</math>  | 
| − | |   | + | |  | 
| − | |   | ||
|  | |  | ||
| + | |||
|-  | |-  | ||
| 4  | | 4  | ||
| 1  | | 1  | ||
| − | | C_4  | + | | <math>C_4</math>  | 
| − | | 1  | + | | 1(1)  | 
| − | + | | <math>\mathcal{O}</math>  | |
| − | |   | + | | <math>\mathcal{O}</math>  | 
| − | |   | + | |  | 
| − | |   | ||
|  | |  | ||
| + | |||
|-  | |-  | ||
| 4  | | 4  | ||
| 2  | | 2  | ||
| − | | <math>C_2 \times C_2<\math>    | + | | <math>C_2 \times C_2</math>   | 
| − | |   | + | | 3(3)  | 
| − | |   | + | | <math>\mathcal{O}</math>  | 
| − | |   | + | | <math>\mathcal{O}</math>  | 
| − | |   | + | |  | 
| − | |   | + | |  | 
| + | |||
| + | |-  | ||
| + | |5  | ||
| + | |1  | ||
| + | |<math>C_5</math>  | ||
| + | |6(6)  | ||
| + | | <math>\mathcal{O}</math>  | ||
| + | | <math>\mathcal{O}</math>  | ||
| + | |  | ||
| + | |||
| + | |-  | ||
| + | |7  | ||
| + | |1  | ||
| + | |<math>C_7</math>  | ||
| + | |14(14)  | ||
| + | |No  | ||
| + | | <math>\mathcal{O}</math>  | ||
| + | |  | ||
| + | |Max 19 classes   | ||
|}  | |}  | ||
Revision as of 09:55, 17 August 2018
Classification of Morita equivalences for blocks with a given defect group
We use the following notation for Morita equivalence classes of blocks of finite groups with respect to an algebraically closed field k.
[math]M(x,y,z)[/math] is a class consisting of blocks with defect groups of order x, with a representative having defect group SmallGroup(x,y) in GAP/MAGMA labelling. It is the z-th such class.
Note that it is not known that the isomorphism class of a defect group is a Morita invariant, so it could be that [math]M(x,y1,z1)=M(x,y2,z2)[/math] for some [math](y1,z1) \neq (y2,z2)[/math].
Also, at present there is no known example of a k-Morita equivalence class of blocks which splits into more than one Morita equivalence class with respect to a complete discrete valuation ring. If such an example arises, then we will bring in more notation for classes with respect to the d.v.r.
| [math]|D|[/math] | SmallGroup | Isotype | Known [math]k[/math]-([math]\mathcal{O}[/math]-)classes | Complete (w.r.t.)? | Derived equiv classes (w.r.t)? | References | Notes | 
|---|---|---|---|---|---|---|---|
| 1 | 1 | 1 | 1(1) | [math]\mathcal{O}[/math] | [math]\mathcal{O}[/math] | ||
| 2 | 1 | [math]C_2[/math] | 1(1) | [math]\mathcal{O}[/math] | [math]\mathcal{O}[/math] | ||
| 3 | 1 | [math]C_3[/math] | 2(2) | [math]\mathcal{O}[/math] | [math]\mathcal{O}[/math] | ||
| 4 | 1 | [math]C_4[/math] | 1(1) | [math]\mathcal{O}[/math] | [math]\mathcal{O}[/math] | ||
| 4 | 2 | [math]C_2 \times C_2[/math] | 3(3) | [math]\mathcal{O}[/math] | [math]\mathcal{O}[/math] | ||
| 5 | 1 | [math]C_5[/math] | 6(6) | [math]\mathcal{O}[/math] | [math]\mathcal{O}[/math] | ||
| 7 | 1 | [math]C_7[/math] | 14(14) | No | [math]\mathcal{O}[/math] | Max 19 classes |