Denoting by
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the linear system of plane curves of degree
dbcaad4d3"" title=""Click to view the MathML source"">d passing through
r+1 generic points
p0,p1,…,pr of the projective plane with multiplicity
mi (or larger) at each
pi, we prove the Harbourne–Hirschowitz Conjecture for linear systems
![]()
determined by a wide family of systems of multiplicities
![]()
and arbitrary degree
d. Moreover, we provide an algorithm for computing a bound for the regularity of an arbitrary system
![]()
, and we give its exact value when
![]()
is in the above family. To do that, we prove an
H1-vanishing theorem for line bundles on surfaces associated with some pencils “at infinity”.