Difference between revisions of "Morita invariants"

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== Invariants preserved under <math>k</math>-Morita equivalence of blocks of finite groups ==
 
== Invariants preserved under <math>k</math>-Morita equivalence of blocks of finite groups ==
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* Cartan matrix, up to rearrangement of rows and columns
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* Order of defect group
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* Exponent of defect group<ref>See (78) of [[References#K|[Ku91]]]</ref>
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* <math>p</math>-rank of defect group<ref>See Corollary 4 of [[References#A|[AE81]]], attributed to Donovan</ref>
  
 
== Invariants preserved under <math>\mathcal{O}</math>-Morita equivalence of blocks of finite groups ==
 
== Invariants preserved under <math>\mathcal{O}</math>-Morita equivalence of blocks of finite groups ==

Revision as of 10:13, 4 January 2019

Under-construction.png

Invariants preserved under Morita equivalence of blocks of f.d. [math]k[/math]-algebras

  • Number of isomorphism classes of simple modules
  • Isomorphism type of centre of algebra, and so dimension of centre
  • Loewy structure and socle structure

Invariants preserved under [math]k[/math]-Morita equivalence of blocks of finite groups

  • Cartan matrix, up to rearrangement of rows and columns
  • Order of defect group
  • Exponent of defect group[1]
  • [math]p[/math]-rank of defect group[2]

Invariants preserved under [math]\mathcal{O}[/math]-Morita equivalence of blocks of finite groups

Invariants preserved under basic Morita equivalence of blocks of finite groups[3]

Invariants preserved under splendid Morita equivalence of blocks of finite groups

Notes

  1. See (78) of [Ku91]
  2. See Corollary 4 of [AE81], attributed to Donovan
  3. Note that by [KL18], if [math]k[/math]-blocks are basic Morita equivalent, then the corresponding [math]\mathcal{O}[/math]-blocks are Morita equivalent