show/hide this revision's text 2 deleted 42 characters in body; added 2 characters in body; added 2 characters in body; added 3 characters in body

I think the right thing to look at is $H^1(X, \mathbb C^*)$. This classifies line bundles with a flat connection(there is no wikipedia link unfortunately), or equivalently, line bundles with locally constant transition functions.

Now the natural embedding $\mathbb C C^* \to \mathbb O_X^$ O_X^*$ induces on a map on cohomology $H^1(X, \mathbb C^C^*) \to H^1(X, \mathbb O_X^*) O_X^*)$ which is forgetting the flat connection.

show/hide this revision's text 1

I think the right thing to look at is $H^1(X, \mathbb C^*)$. This classifies line bundles with a flat connection (there is no wikipedia link unfortunately), or equivalently, line bundles with locally constant transition functions.

Now the natural embedding $\mathbb C \to \mathbb O_X^$ induces on a map on cohomology $H^1(X, \mathbb C^) \to H^1(X, \mathbb O_X^*) which is forgetting the flat connection.