We construct a polyhedron that is topologically convex (i.e., has the graph of a convex polyhedron) yet has no vertex unfolding: no matter how we cut along the edges and keep faces attached at vertices to form a connected (hinged) surface, the surface necessarily unfolds with overlap.

Ömür Deveci1, 2 and Erdal Karaduman1,2 1 Department of Mathematics, Faculty of Arts and Science, Kafkas University, 36100 Kars, Turkey 2 Department of Mathematics, Faculty of Science, Atatürk University, 25240 Erzurum, Turkey Correspondence should be addressed to Ömür Deveci, [email protected] Received 18 October 2011; Accepted 11 December 2011 Academic Editor: Reinaldo Martinez Palhares C...

Classical polyhedral representations of imperative languages entangle untranslated scalar imperative operations to the declarative descriptions of the polyhedral model. This representation can handle high level array operations, but is more difficult to work on programs that split the array computations in smaller chunks involving scalar temporary variables. The aim of the current paper is to p...

We show that no minimal vertex triangulation of a closed, connected, orientable 2-manifold of genus 6 admits a polyhedral embedding in R. We also provide examples of minimal vertex triangulations of closed, connected, orientable 2-manifolds of genus 5 that do not admit any polyhedral embeddings. We construct a new infinite family of non-realizable triangulations of surfaces. These results were ...

A polyhedral map is called {p, q}-equivelar if each face has p edges and each vertex belongs to q faces. In [12], it was shown that there exist infinitely many geometrically realizable {p, q}-equivelar polyhedral maps if q > p = 4, p > q = 4 or q − 3 > p = 3. It was shown in [6] that there exist infinitely many {4, 4}and {3, 6}-equivelar polyhedral maps. In [1], it was shown that {5, 5}and {6, ...

We present a new library for extracting a polyhedral model from C source. The library is based on clang, the LLVM C frontend, and isl, a library for manipulating quasi-affine sets and relations. The use of clang for parsing the C code brings advanced diagnostics and full support for C99. The use of isl allows for an easy construction and a powerful and compact representation of the polyhedral m...

The polyhedral model provides a powerful mathematical abstraction to enable effective optimization of loop nests with respect to a given optimization goal, e.g., exploiting parallelism. Unexploited reduction properties are a frequent reason for polyhedral optimizers to assume parallelism prohibiting dependences. To our knowledge, no polyhedral loop optimizer available in any production compiler...