2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/60491We describe a family of $q$-series generating the space of weight 1 modular forms coming from indefinite binary quadratic forms and study linear relations between these series.9 pages, AMSLatex, minor correctionsNumber TheoryAlgebraic GeometryA new look at Hecke's indefinite theta seriestext