TITLE: Wrong Tits-Index of E7 from Springer 's book
QUESTION [5 upvotes]: In the his book
Linear algebraic groups, by T.A. Springer,
there is a list of possible Tits-Indexes. For the $E_7$ case, there is an index shown, such that vertex $1$ and $7$ are circled (Bourbaki notation). I just realized that yesterday by coincidence. However in Tits's original paper this index is not listed. On top of that neither here
http://arxiv.org/pdf/1511.02538.pdf
nor here
http://arxiv.org/abs/0807.2140
do we find it.
What did go wrong in Springers book?

REPLY [10 votes]: That is a typo. In index 14 on p. 321 the vertex 6 should be black. In Proposition 17.8.2, this index is correct. It corresponds to $E_{7,3}^{28}$ in Tits' notation.