ESI The Erwin Schr odinger

ESI The Erwin Schr odinger

ESI The Erwin Schr odinger

ESI The Erwin Schr odinger

ESI The Erwin Schr odinger

2 ABSTRACT In this paper we explicitly prove the invariance of the time-dependent string gravity Lagrangian with up to four derivatives under the global O(d; d) symmetry.

ESI The Erwin Schr odinger

3 We consider commuting squares of nite dimensional von Neumann algebras having the algebra of complex numbers in the lower left corner. Examples include the vertex models, the spin models (in the sense of subfactor theory) and the commuting squares associated to nite dimensional Kac algebras. To any such commuting square we associate a compact Kac algebra and we compute the corresponding subfa...