Validation Categories
Validation categories specify the circumstances in which the problem or solution is valid. You can classify problems or solutions by one or more validation categories.
Example
A validation category could be a specific version, release, revision,
or series such as Printer Series 5.0
or Printer
Series 5.1
.
End of the example.
Validation categories are defined by your system administrator
in Customizing for Customer Relationship Management
,
by choosing 
Enterprise Intelligence
Solution Database
Basic Data
Define Validation Categories
.