# Maximal torus and application in prime graph [closed]

I am studying papers about " Prime graph" , for example "Prime graph components of finite groups" [ williams], " Groups with complete prime graph connected components" [ Lucido and moghaddanfar]. But I do not understand some of scientific terms in papers to relate this matter. For example, concepts like torus, maximal tori. Can someone explain these terms? How these concepts are used in these articles?

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## closed as off-topic by Gjergji Zaimi, Andy Putman, Andrey Rekalo, Chris Godsil, Todd Trimble♦Jun 30 '13 at 1:56

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They are talking about maximal tori in finite groups of Lie type. See e.g. the books by Carter (ams.org/mathscinet-getitem?mr=794307) or Malle-Testerman (ams.org/mathscinet-getitem?mr=2850737). –  Francois Ziegler Jun 28 '13 at 17:58
Thank you for your response –  mousavi Jun 29 '13 at 6:28

We know that each torus is a maximal abelian subgroup and so the prime divisors of $|T|$ are mutually adjacent in the prime graph of $G$.