is there an explicit construction of Ramanujan graphs (preferably in GAP)?

78 Views Asked by At

This book gives explicit constructions of Ramanujan expander graphs $X^{p,q}$ in terms of Cayley graphs of subsets in $PSL(2,q)$ or $PGL(2,q)$. It seems there's enough detail to write a program in GAP that does what the book describes but I'm sure it will take some effort. I'm hoping that someone has already done that. Does anyone know if this is the case?