Abstract (EN):
Let U ¿ H0(O¿1׿1 (a, b)) be a basepoint free four-dimensional vector space, with a, b ¿ 2. The sections corresponding to U determine a regular map ¿U : ¿1 × ¿1 ¿ ¿3. We show that there can be at most one linear syzygy on the associated bigraded ideal IU ¿ k[s, t; u, v]. Existence of a linear syzygy, coupled with the assumption that U is basepoint free, implies the existence of an additional ¿special pair¿ of minimal first syzygies. Using results of Botbol, we show that these three syzygies are sufficient to determine the implicit equation of ¿U (¿1 × ¿1), and that Sing(¿U (¿1 × ¿1)) contains a line.
Language:
English
Type (Professor's evaluation):
Scientific
No. of pages:
7