Towards an Algebraic Classification of Calabi-Yau Manifolds I: Study of   K3 Spaces
  We present an inductive algebraic approach to the systematic construction and classification of generalized Calabi-Yau (CY) manifolds in different numbers of complex dimensions, based on Batyrev's formulation of CY manifolds as toric varieties in weighted complex projective spaces associated with reflexive polyhedra. We show how the allowed weight vectors in lower dimensions may be extended to higher dimensions, emphasizing the roles of projection and intersection in their dual description, and the natural appearance of Cartan-Lie algebra structures. The 50 allowed extended four-dimensional vectors may be combined in pairs (triples) to form 22 (4) chains containing 90 (91) K3 spaces, of which 94 are distinct, and one further K3 space is found using duality. In the case of CY_3 spaces, pairs (triples) of the 10~270 allowed extended vectors yield 4242 (259) chains with K3 (elliptic) fibers containing 730 additional K3 polyhedra. A more complete study of CY_3 spaces is left for later work. 
F. Anselmo (INFN Bologna), J. Ellis (CERN), D.V. Nanopoulos (Texas   A&M, HARC, Academy of Athens), G. Volkov (CERN, IHEP Pr...