These slides are good also: "The ADE affair" Peter J. Cameron http://www-groups.mcs.st-andrews.ac.uk/~pjc/talks/boundaries/ade2.pdf http://www-groups.mcs.st-an

These slides are good also: "The ADE affair" Peter J. Cameron http://www-groups.mcs.st-andrews.ac.uk/~pjc/talks/boundaries/ade2.pdf http://www-groups.mcs.st-andrews.ac.uk/~pjc/talks/boundaries...