SysML is some kind of UML dialect.
SysML = UML++--
i.e. SysML has more than UML, e.g. the requirements diagram, and SysML
has less
than UML, e.g. the component model and some diagram types. In summary
SysML is
a smaller language than UML.
More information:
A short description of SysML: http://www.omgsysml.org
A book about SysML: http://www.system-modeling.com
Regards,
Tim