Dyna Glossary
- functor
- The constructor of a term, such as path in path(1,2).
- null
- The value of items that have no rules contributing aggregands.
Null annihilates expressions (e.g. \(\mbox{null} + 2\)
is \(\mbox{null}\)) and is the unit of aggregations
(e.g. \(\sum\{\mbox{null}, 1, \mbox{null}, 2\}\) is
just \(\sum\{1,2\}\)).