Talk:Dempwolff group

Where is this group constructed?

Where did an existence proof of this nonsplit extension first appear? I'm not an expert here, but I seem to see that the Dempwolff Rend. Sem. Mat. Univ. Padova (1972) article treats uniqueness, the other article by the same author in J. Austral. Math. Soc. (1973) treats the case of extensions of 2ⁿ by GL(n,2) for n≠5, the Thompson J. Algebra (1976) article seems to show the embedding of the Dempwolff group in E₈(C) only assuming its existence ("it is shown elsewhere that L(ℱ) contains a sublattice Λ with the property that the group of all automorphisms of ℒ (as a Lie algebra) that fix Λ is a nonsplitting extension of Z₂⁵ by L₅(2)"). The "elsewhere" is supposedly an article by Smith and Thompson, but it seems to have remained unpublished. Lastly, there is the Griess J. Algebra (1976) article (“On a subgroup of order 2¹⁵|GL(5,2)| in E₈(C), the Dempwolff group and Aut(D₈∘D₈∘D₈)”), which probably should be mentioned here, and which may or may not constitute an independent existence proof of the Dempwolff group, I am not sure (again, it refers to an unpublished result of Smith, but does not seem to actually depend on it). Clarification, anyone? --Gro-Tsen (talk) 08:51, 22 November 2010 (UTC)