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)<\math> for some <math>(y1,z1) \neq (y2,z2)<\math>.
+
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-classes
+
! scope="col"| Known <math>k</math>-(<math>\mathcal{O}</math>-)classes
! scope="col"| O-classes
+
! scope="col"| Complete (w.r.t.)?
! scope="col"| Complete w.r.t. k?
+
! scope="col"| Derived equiv classes (w.r.t)?
! scope="col"| Complete w.r.t. O?
+
! scope="col"| References
! scope="col"| Broue?
 
 
! scope="col"| Notes
 
! scope="col"| Notes
 
|-
 
|-
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| 1  
 
| 1  
 
| 1  
 
| 1  
| 1  
+
| 1(1)
| 1  
+
| <math>\mathcal{O}</math>
| Yes
+
| <math>\mathcal{O}</math>
| Yes
 
| Yes
 
 
|  
 
|  
 +
 
|-
 
|-
 
| 2  
 
| 2  
 
| 1  
 
| 1  
| C_2  
+
| <math>C_2</math>
| 1  
+
| 1(1)
| 1  
+
| <math>\mathcal{O}</math>
| Yes
+
| <math>\mathcal{O}</math>
| Yes
 
| Yes
 
 
|  
 
|  
 +
 
|-
 
|-
 
| 3
 
| 3
 
| 1
 
| 1
| C_3
+
| <math>C_3</math>
| 2
+
| 2(2)
| 2
+
| <math>\mathcal{O}</math>
| Yes
+
| <math>\mathcal{O}</math>
| Yes
+
|
| Yes
 
 
|
 
|
 +
 
|-
 
|-
 
| 4
 
| 4
 
| 1
 
| 1
| C_4
+
| <math>C_4</math>
| 1
+
| 1(1)
| 1
+
| <math>\mathcal{O}</math>
| Yes
+
| <math>\mathcal{O}</math>
| Yes
+
|
| Yes
 
 
|
 
|
 +
 
|-
 
|-
 
| 4
 
| 4
 
| 2
 
| 2
| <math>C_2 \times C_2<\math>  
+
| <math>C_2 \times C_2</math>
| 3
+
| 3(3)
| 3
+
| <math>\mathcal{O}</math>
| Yes
+
| <math>\mathcal{O}</math>
| Yes
+
|
| Yes
+
|
 +
 
 +
|-
 +
|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 10:55, 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