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In doing linear systems, divisor and

EDIT: Let me try to make the question clearer.

Consider the invertible sheaves $\mathcal{O}(d)$ over algebraic varieties we might find that one of the more accessible examples are projective space $\mathbb{P}^n$ and where $d\in \mathbb{Z}$. Now, if $d>0$, among many properties, it is known that the invertible space of global sections of such sheaves $\mathcal{O}(d)$ over them. Such sheaves can give us V=\Gamma({\mathbb{P}^n},\mathcal{O}(d))$ encode information about embeddings (d-uple in particular), divisors whose Poincare dual class in cohomology is the Chern class of between the associated line bundle that it may represent, so on projective spaces $\mathbb{P}^n$ and so forth. $\mathbb{P}(V)=\mathbb{P}^N$.

My question is the following. Considerng the projective space, what What kind of information carry do the sheaves $\mathcal{O}(-d)$ where \mathcal{O}(d)$ encode when $d>0$?. d<0$?. By "information" I know that the kind of properties mean, in such sheaves are not similar to those of $\mathcal{O}(d)$. But which context do they ought appear and seem to have some information about $\mathbb{P}^n$ or notbe helpful?

References are very welcome.
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Nature of Invertible Sheaves in which there are no global sections.

In doing linear systems, divisor and invertible sheaves over algebraic varieties we might find that one of the more accessible examples are $\mathbb{P}^n$ and the invertible sheaves $\mathcal{O}(d)$ over them. Such sheaves can give us information about embeddings (d-uple in particular), divisors whose Poincare dual class in cohomology is the Chern class of the associated line bundle that it may represent, so on and so forth. My question is the following. Considerng the projective space, what kind of information carry the sheaves $\mathcal{O}(-d)$ where $d>0$?. I know that the kind of properties in such sheaves are not similar to those of $\mathcal{O}(d)$. But they ought to have some information about $\mathbb{P}^n$ or not?

References are very welcome.