If (g,d) belongs to ((16,17),(17,18),(18,19),(19,20),(20,20)), then the function returns a list (a,b1,...,b10) with the following feature: if we consider an Alexander surface, i.e., the blow up of P2 along 10 general points pi embedded in P4 via |13L-4(p1+...+p10)|, then the strict transform of a general curve in the linear system |a*L-b1*p1-...-b10*p10| will be a smooth curve of genus g and degree d in P4
i1 : linSysAlexander(16,17)
o1 = {21, 7, 7, 7, 7, 6, 6, 6, 6, 6, 6}
o1 : List
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i2 : try linSysAlexander(12,14) else "not implemented" o2 = not implemented |