This page describes currently proposed language for meta-descriptions. It may be updated frequently.

= Relational operators =
Standard relational operators apply
||Meaning         || Operator ||
||Less than       ||<         ||
||Less or equal   ||<=        ||
||Greater than    ||>         ||
||Greater or equal||>=        ||
||Equal           ||==        ||
||Different than  ||!=        ||

= Logical operators =
Standard logical operators apply
||Meaning || Operator ||
||And	  || and      ||
||Or	  || or       ||
||Xor	  || xor      ||
||Not	  || not      ||

For events in the timeline of events, using ''and'' or ''or'' operators denotes that any ordering between these events is possible.

= Arithmetic operators =
Standard arithmetic operators apply and parenthesis are used for non-obvious precedence

= Temporal operators =
We want to be able to denote order and concurrency of events and state changes, and duration of events.
||Meaning	                   || Operator and example ||
||A occurs after B                 || B -> A               ||
||A and B occur concurrently       || A | | B              ||            
||A lasts T time	           || A,,T,,               ||
||A occurs T time after B	   || B ->,,T,, A          ||

= Existential, cardinality and modal operators =
We want to be able to denote how many objects or events of a given type must/may occur.
Meaning	Operator and example
||Every object A	             || each A     ||
||Some objects A	             || some A     ||
||Some object A called a1            || some A a1  ||
||A must occur	                     || A          ||
||A may occur	                     || [A]        ||
||Exactly N objects/events of type A || |A|,,N,,   ||
||At least N objects/events of type A|| |A|,,>=N,, ||
||At most N objects/events of type A || |A|,,<=N,, ||