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Let $X$ be a smooth degree $d$ ($d>5$) surface in $\mathbb{P}^3$. We now blow up $X$ at a point, embed it in some projective space, and and consider a projection of it into $\mathbb{P}^3$. The question is does this resulting surface have only ADE singularities? If not when is it the case? What is the degree of the final surface?

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The phrasing could use a little work. Given that your blowup Y of X cannot be embedded in P^3 (the canonical bundle is of the wrong type) I assume you are asking for an embedding of Y in some projective space together with a projection from Y to P^3 which is birational onto its image and has only ADE singularities. Is this correct? –  Yusuf Mustopa Mar 5 '13 at 1:44
@Mustopa: Thank you. You are completely correct. –  Naga Venkata Mar 5 '13 at 6:59
If you do not fix the embedding of Y into a projective space, the degree can be almost anything (with fixed d). –  Jérémy Blanc Mar 5 '13 at 12:24

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