| AggregateAtom | This class represents an aggregate. | 
| AggregateElement | This class models an aggregate element, meaning a set of terms and a set of
 naf literals (= literals or default negated literals). | 
| AggregateHead | This class is a variant of the basic ASP rule head. | 
| ArithmeticTerm | This class represents an arithmetic term in the ASP-Core-2 format. | 
| ASPAtom | This class models an atom, which is a basic structure for building literals
 and rules for logic programs. | 
| ASPBodyElement | This class is a common base class for ASP formulas
 that can be part of an ASP rule body (premise of a rule): 
 
 
  Literals (i.e. | 
| ASPElement | This class acts as an abstract base class for elements
 of ASP rules. | 
| ASPHead | This class is a common base class for ASP formulas
 that can be part of an ASP rule head. | 
| ASPLiteral | This class defines common functionality for literals,
 meaning atoms or strictly negated atoms. | 
| ASPOperator | This class collects some common operators used in ASP terms
 as well as the possible function names for aggregates. | 
| ASPRule | This class models a rule in ASP. | 
| ClassicalHead | This formula represents the head of an disjunctive rule which is a
 disjunction of literals. | 
| ComparativeAtom | This class represents a comparative atom, meaning an expression of the form 't x u'
 where t,u are terms and x is in {<, <=, ==, !=, >, >=}. | 
| DefaultificationTest |  | 
| DefaultNegation | This class represents a default negated literal, i.e. | 
| EqualsTester |  | 
| OptimizationElement | This class represents an element of an optimization statement, meaning
 a term-literal tuple that is associated with a weight and optionally
 a priority (level). | 
| OptimizationStatement | This class represents an optimization statement. | 
| Program | This class models an ASP-Core-2 program, meaning a set of rules and
 optionally a query. | 
| StrictNegation | This class models the strict negation of an atom (as opposed to a default
 negation:  DefaultNegation). |