Difference between revisions of "SD16"

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(Blocks with defect group SD_{16}: Added note about Monster group)
 
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== Blocks with defect group <math>SD_{16}</math> ==
 
== Blocks with defect group <math>SD_{16}</math> ==
  
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These are examples of [[Tame blocks|tame blocks]] and were first classified over <math>k</math> by Erdmann (see [[References|[Er88c], [Er90b]]]). Further work was carried out in [[References#M|[Mac]]], where <math>SD(3 {\cal H})</math> was eliminated, and the block <math>B_0(kPSL_3(3))</math> reattributed to <math>SD(3 {\cal D})</math>, so that the class <math>SD(3 {\cal B})_1</math> is now a class of algebras with no known block-realised representative. It is not known whether there are blocks realising the class <math>SD(3 {\cal C})_2</math>.
  
[[Image:under-construction.png|50px|left]]
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Until these remaining cases are resolved the labelling is provisional.
  
These are examples of [[Tame blocks|tame blocks]] and were first classified over <math>k</math> by Erdmann (see [[References|[Er88c], [Er90b]]]). The classification with respect to <math>\mathcal{O}</math> is still unknown.
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The classification with respect to <math>\mathcal{O}</math> is still unknown.
  
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'''<pre style="color: red">CLASSIFICATION INCOMPLETE</pre>'''
  
 
{| class="wikitable"
 
{| class="wikitable"
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|[[M(16,8,1)]] || <math>kSD_{16}</math> || 1 ||7 ||1 ||<math>1</math> || || || ||1 ||
 
|[[M(16,8,1)]] || <math>kSD_{16}</math> || 1 ||7 ||1 ||<math>1</math> || || || ||1 ||
 
|-
 
|-
|[[M(16,8,2)]] || <math>B_5(kPSU_3(5))</math> || ? ||7 ||2 ||<math>1</math> || || || ||1 || <math>SD(2 {\cal A})_1</math>
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|[[M(16,8,2)]] || <math>B_5(kPSU_3(5))</math> || ? ||8 ||2 ||<math>1</math> || || || ||1 || <math>SD(2 {\cal A})_1</math>
 
|-
 
|-
|[[M(16,8,3)]] || || ? ||7 ||2 ||<math>1</math> || || || ||1 || <math>SD(2 {\cal A})_2</math>
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|[[M(16,8,3)]] || <math>B_0(kM_{10})=B_0(k(A_6.2_3))</math> || ? ||7 ||2 ||<math>1</math> || || || ||1 || <math>SD(2 {\cal A})_2</math>
 
|-
 
|-
 
|[[M(16,8,4)]] || <math>B_3(k(3.M_{10}))=B_3(k(3.A_6.2_3))</math> || ? ||7 ||2 ||<math>1</math> || || || ||1 || <math>SD(2 {\cal B})_1</math>
 
|[[M(16,8,4)]] || <math>B_3(k(3.M_{10}))=B_3(k(3.A_6.2_3))</math> || ? ||7 ||2 ||<math>1</math> || || || ||1 || <math>SD(2 {\cal B})_1</math>
 
|-
 
|-
|[[M(16,8,5)]] || || ? ||7 ||2 ||<math>1</math> || || || ||1 || <math>SD(2 {\cal B})_2</math>
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|[[M(16,8,5)]] || <math>B_1(kPSL_3(11))</math> || ? ||8 ||2 ||<math>1</math> || || || ||1 || <math>SD(2 {\cal B})_2</math>
 
|-
 
|-
|[[M(16,8,6)]] || || ? ||7 ||3 ||<math>1</math> || || || ||1 || <math>SD(3 {\cal A})_1</math>
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|[[M(16,8,6)]] || <math>B_0(kPSU_3(5))</math> || ? ||8 ||3 ||<math>1</math> || || || ||1 || <math>SD(3 {\cal A})_1</math>
 
|-
 
|-
|[[M(16,8,7)]] || || ? ||7 ||3 ||<math>1</math> || || || ||1 || <math>SD(3 {\cal B})_1</math>
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|[[M(16,8,7)]] || <math>B_0(kPSL_3(3))</math> || ? ||8 ||3 ||<math>1</math> || || || ||1 || <math>SD(3 {\cal D})</math>. See note above.
 
|-
 
|-
|[[M(16,8,8)]] || || ? ||7 ||3 ||<math>1</math> || || || ||1 || <math>SD(3 {\cal C})_2</math>
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| || || ? ||8 ||3 ||<math>1</math> || || || ||1 || <math>SD(3 {\cal B})_1</math>
 
|-
 
|-
|[[M(16,8,9)]] || || ? ||7 ||3 ||<math>1</math> || || || ||1 || <math>SD(3 {\cal D})</math>
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| || || ? ||8 ||3 ||<math>1</math> || || || ||1 || <math>SD(3 {\cal B})_2</math> or <math>SD(3 {\cal C})_2</math><ref>See discussion in [[References#M|[Mac]]]: A block of the Monster group could be in one or other of these classes.</ref>
|-
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|[[M(16,8,10)]] || || ? ||7 ||3 ||<math>1</math> || || || ||1 || <math>SD(3 {\cal H})</math>
 
 
|}
 
|}
  
<!-- [[M(8,3,2)]] and [[M(8,3,3)]] are derived equivalent over <math>k</math> by [[References|[Ho97] ]].
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[[M(16,8,2)]] and [[M(16,8,5)]] are derived equivalent over <math>k</math> by [[References|[Ho97] ]].
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[[M(16,8,3)]] and [[M(16,8,4)]] are derived equivalent over <math>k</math> by [[References|[Ho97] ]].
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All Morita equivalence classes with three simple modules are derived equivalent over <math>k</math> by [[References|[Ho97] ]].
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== Notes ==
  
[[M(8,3,4)]], [[M(8,3,5)]] and [[M(8,3,6)]] are derived equivalent over <math>k</math> by [[References|[Li94b] ]].-->
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<references />

Latest revision as of 14:34, 4 August 2022

Blocks with defect group [math]SD_{16}[/math]

These are examples of tame blocks and were first classified over [math]k[/math] by Erdmann (see [Er88c], [Er90b]). Further work was carried out in [Mac], where [math]SD(3 {\cal H})[/math] was eliminated, and the block [math]B_0(kPSL_3(3))[/math] reattributed to [math]SD(3 {\cal D})[/math], so that the class [math]SD(3 {\cal B})_1[/math] is now a class of algebras with no known block-realised representative. It is not known whether there are blocks realising the class [math]SD(3 {\cal C})_2[/math].

Until these remaining cases are resolved the labelling is provisional.

The classification with respect to [math]\mathcal{O}[/math] is still unknown.

CLASSIFICATION INCOMPLETE
Class Representative # lifts / [math]\mathcal{O}[/math] [math]k(B)[/math] [math]l(B)[/math] Inertial quotients [math]{\rm Pic}_\mathcal{O}(B)[/math] [math]{\rm Pic}_k(B)[/math] [math]{\rm mf_\mathcal{O}(B)}[/math] [math]{\rm mf_k(B)}[/math] Notes
M(16,8,1) [math]kSD_{16}[/math] 1 7 1 [math]1[/math] 1
M(16,8,2) [math]B_5(kPSU_3(5))[/math]  ? 8 2 [math]1[/math] 1 [math]SD(2 {\cal A})_1[/math]
M(16,8,3) [math]B_0(kM_{10})=B_0(k(A_6.2_3))[/math]  ? 7 2 [math]1[/math] 1 [math]SD(2 {\cal A})_2[/math]
M(16,8,4) [math]B_3(k(3.M_{10}))=B_3(k(3.A_6.2_3))[/math]  ? 7 2 [math]1[/math] 1 [math]SD(2 {\cal B})_1[/math]
M(16,8,5) [math]B_1(kPSL_3(11))[/math]  ? 8 2 [math]1[/math] 1 [math]SD(2 {\cal B})_2[/math]
M(16,8,6) [math]B_0(kPSU_3(5))[/math]  ? 8 3 [math]1[/math] 1 [math]SD(3 {\cal A})_1[/math]
M(16,8,7) [math]B_0(kPSL_3(3))[/math]  ? 8 3 [math]1[/math] 1 [math]SD(3 {\cal D})[/math]. See note above.
 ? 8 3 [math]1[/math] 1 [math]SD(3 {\cal B})_1[/math]
 ? 8 3 [math]1[/math] 1 [math]SD(3 {\cal B})_2[/math] or [math]SD(3 {\cal C})_2[/math][1]

M(16,8,2) and M(16,8,5) are derived equivalent over [math]k[/math] by [Ho97] .

M(16,8,3) and M(16,8,4) are derived equivalent over [math]k[/math] by [Ho97] .

All Morita equivalence classes with three simple modules are derived equivalent over [math]k[/math] by [Ho97] .


Notes

  1. See discussion in [Mac]: A block of the Monster group could be in one or other of these classes.