1. The open mouth theorem, or the scissors lemma, for orthocentric tetrahedra

   • Sadi Abu-Saymeh
   • Mowaffaq Hajja
   • Mostafa Hayajneh

   OriginalPaper 22 June 2012 Pages: 1 - 16

2. Factorable surfaces in the three-dimensional Euclidean and Lorentzian spaces satisfying Δr _i  = λ _i r _i

   • Mohammed Bekkar
   • Bendehiba Senoussi

   OriginalPaper 21 June 2012 Pages: 17 - 29

3. Clifford parallelism: old and new definitions, and their use

   • Dieter Betten
   • Rolf Riesinger

   OriginalPaper 27 June 2012 Pages: 31 - 73

4. The realizable extension problem and the weighted graph (K _3,3, l)

   • Jonathan McLaughlin

   OriginalPaper 17 April 2012 Pages: 75 - 88

5. Conformally invariant tensors of an almost Hermitian manifold associated with the holomorphic curvature tensor

   • Mileva Prvanović

   OriginalPaper 17 May 2012 Pages: 89 - 101

6. Splints of classical root systems

   • David A. Richter

   OriginalPaper 29 April 2012 Pages: 103 - 117

7. Parallelism in K-contact geometry

   • Philippe Rukimbira

   OriginalPaper 20 June 2012 Pages: 119 - 123

8. Extremal problems for the central projection

   • Shigehiro Sakata

   OriginalPaper 17 April 2012 Pages: 125 - 129

9. Conics in the hyperbolic plane intrinsic to the collineation group

   • John Sarli

   OriginalPaper 22 June 2012 Pages: 131 - 148

10. Convex solids whose point-source shadow-boundaries lie in hyperplanes

    • Valeriu Soltan

    OriginalPaper 17 April 2012 Pages: 149 - 160

11. On the semidiscrete differential geometry of A-surfaces and K-surfaces

    • Johannes Wallner

    OriginalPaper 07 April 2012 Pages: 161 - 176

12. Linear Weingarten spacelike submanifolds in de Sitter space

    • Dan Yang
    • Zhonghua Hou

    OriginalPaper 18 April 2012 Pages: 177 - 190