## Convex decompositions of real projective surfaces. I: $$\pi$$-annuli and convexity.(English)Zbl 0818.53042

The author considers an orientable compact projective surface $$\Sigma$$ with convex boundary and negative Euler characteristic. He supposes that $$\Sigma$$ is not convex. He proves in his main result that there is a $$\pi$$-annulus $$\Lambda$$ with a projective map $$\Phi: \Lambda\to \Sigma$$.

### MSC:

 53C15 General geometric structures on manifolds (almost complex, almost product structures, etc.)
Full Text: