  In this paper we study symmetrizable intersection matrices, namely
generalized intersection matrices introduced by P. Slodowy such that they are
symmetrizable. Every such matrix can be naturally associated with a root basis
and a Weyl root system. Using $d$-fold affinization matrices we give a
classification, up to braid-equivalence, for all positive semi-definite
symmetrizable intersection matrices. We also give an explicit structure of the
Weyl root system for each $d$-fold affinization matrix in terms of the root
system of the corresponding Cartan matrix and some special null roots.
