Generalized D-Forms Have No Spurious Creases
A convex surface that is flat everywhere but on finitely many smooth curves (or seams) and points is a seam form. We show that the only creases through the flat components of a seam form are either between vertices or tangent to the seams. As corollaries we resolve open problems about certain special seam forms: the flat components of a D-form have no creases at all, and the flat component of a pita-form has at most one crease, between the seam's endpoints.
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