A note on sheaves without self-extensions on the projective $n$-space
  Let ${\bf P}^n$ be the projective $n-$space over the complex numbers. In this note we show that an indecomposable rigid coherent sheaf on ${\bf P}^n$ has a trivial endomorphism algebra. This generalizes a result of Drezet for $n=2.$ 
Dieter Happel and Dan Zacharia
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