2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/60624The moduli space of abelian surfaces with polarisation of type (1,6) and a bilevel structure has positive Kodaira dimension. By contrast, Mukai has shown that the moduli space of bilevel-t abelian sufaces is rational for t=2,3,4,5.9 pages, plain TeX. Results improved and extended: an error correctedAlgebraic Geometry14J15; 14K10; 11F46text