Initial State: | conjunction of function free ground literals. In STRIPS no negative literals can be used in the initial state. In PDDL negative literals are allowed, but with the closed world assumption, whatever is not explicitely stated is assumed to be false. |
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Goal: | conjunction of literals. variables are allowed. (Implicitely) they are considered existentially quantified. In STRIPS no variables are allowed in goals, but there can be variables in PDDL. |

Preconditions: | conjunction of literals. In STRIPS no negative literals can be used in the preconditions. Variables are allowed. Most of the time, the variables used are the ones in the list of variables for the action schema. If they are not, (implicitely) they are considered existentially quantified. |

Effects: | conjunction of positive and negative literals. The interpretation is that positive literals describe what is added to the world as an effect of the action and negative literals describe what is deleted from the world. |

Goal: | conjunction of positive ground literals
+ conjunction of negative literals
+ disjunction of positive or negative literals + variables are (implicitely) considered existentially quantified.
+ universally quantified variables are allowed |
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Preconditions: | conjunction of positive literals. + disjunction of positive literals. A disjunction such as "p or q" requires a non deterministic choice. The same effect could be achieved less efficiently by writing two separate operators, one with "p" and one with "q" as precondition. Example: part-of(p,w) or single(p) + existentially quantified variables are allowed
+ universally quantified variables allowed |

Effects: | conjunction of positive and negative literals. Disjunctions are not allowed since this would introduce non determinism.
+ universally quantified variables allowed
+ conditional effects, where both the antecedent (or condition)
and the consequent (or effect) are conjunctions of literals. |

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