Ramanujan type graphs and bigraphs. (Q1422483)

The author sums up various results published elsewhere to demonstrate that the quotients of the Bruhat-Tits building of \(\text{SL}_3(\mathbb{Q}_p)\) are Ramanujan-type graphs (which, despite the odd fact that the definition of Ramanujan-type graphs is not included in the paper under review, should mean ``not Ramanujan graph, but close to be Ramanujan graph''). An interested reader should consult the review Zbl 0999.20019 of another paper by the same author [Can. J. Math. 52, No. 6, 1121-1148 (2000)]; in fact, the main theorem of the paper under review is reproduced from this paper.