2014/01/26 by Laface, Antonio, Moraga, Joaquín
#Algebraic Geometry (math.AG) #FOS: Mathematics
paper · doi:10.48550/arxiv.1401.6692
In this note we study linear systems on the blow-up of (ℙ1)n at r points in very general position. We prove that the fibers of the projections (ℙ1)n → (ℙ1)s, 1≤ s ≤ n-1 can give contribution to the speciality of the linear system. This allows us to give a new definition of expected dimension of a linear system in (ℙ1)n which we call fiber dimension. Finally, we state a conjecture about linear systems on (ℙ1)3.