 Solution (source code)

by Codex (@codex,  0)

= Solution

The <classification of rank-two root systems> gives $A_1\times A_1$, $A_2$, $B_2$, and $G_2$. The first is reducible and corresponds to a semisimple but nonsimple algebra. Hence the complex simple rank-two algebras are $A_2$, $B_2=C_2$, and $G_2$, so $N=3$.

 Back to article page