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 | ||
|- | |- | ||
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| 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 |