  Riemannian symmetric spaces are fundamental objects in finite dimensional
differential geometry. An important problem is the construction of symmetric
spaces for generalizations of simple Lie groups, especially their closest
infinite dimensional analogues known as Kac-Moody groups. We solve this problem
and construct affine Kac-Moody symmetric spaces in a series of several papers.
This paper focuses on the algebraic side: More precisely, we introduce OSAKAs,
the algebraic structures used to describe the connection between affine
Kac-Moody symmetric spaces and affine Kac-Moody algebras and describe their
classification.
