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Sep 12, 2023 at 9:51 vote accept kindasorta
Sep 11, 2023 at 16:35 answer added David E Speyer timeline score: 3
Sep 11, 2023 at 16:34 review Close votes
Sep 17, 2023 at 3:05
Sep 11, 2023 at 16:34 comment added kindasorta As far as injectivity goes, the exercise should be something like: assume there is an effective degree 2 divisir $P+Q$ on $C$, and another one $R+S$, which are linearly equivalent, then there is a non-trivial degree 2 automorphism of $C$?
Sep 11, 2023 at 16:32 comment added kindasorta First off: many thanks. I am away from my computer, if it is not too much of a burden could you find the reference in Arbarello et al?
Sep 11, 2023 at 16:11 comment added abx Any book on curves — e.g. Arbarello et al. But at least for the injectivity, work it out by yourself, it follows directly from the definitions.
Sep 11, 2023 at 15:59 comment added kindasorta Why is it the case? Do you have any references?
Sep 11, 2023 at 15:52 comment added abx It is not an embedding if and only if $C$ admits a linear series of degree 2 and dimension $>0$, that is, if and only if $C$ is hyperelliptic.
Sep 11, 2023 at 15:14 history asked kindasorta CC BY-SA 4.0