|PATRICE SAWYER, Department of Mathematics and Computer Science, Laurentian University, Sudbury, Ontario P3E 2C6, Canada|
|Ghostly symmetric spaces|
Various objects associated with symmetric spaces have specific ranges. We are thinking in particular of root multiplicities in the root system (nonnegative integers) and of the Cartan subalgebra (). We will see that by extending these ranges and thus going beyond the ``physical'' symmetric spaces (hence the title), we can solve problems concerning ordinary symmetric spaces.