TARGET DECK: Main Deck
What is a predicate $p$? #fc
A boolean function
What are types (in PDDL), ie. how are they formulated? #fc
As unary predicates
What is a fact in PDDL? #fc
It is a predicate $p$ evaluated on an object tuple $\bar{x}$ that evaluates to true
What is a literal in PDDL? #fc
A fact or negated fact
What is a state in PDDL? #fc
A set of literals
What are the three components of a PDDL action? #fc
- parameter tuple $\bar{X} = \langle X_1, ..., X_k \rangle$
- literal preconditions $pre(a)$
- literal effects $eff(a)$
What is an action instance (as opposed to an action)? #fc
It is anaction with it's parameters $\bar{X}$ replaced with objects $\bar{x}$.
When is an action instance applicable in state $\mathcal I$? #fc
If $(pre^+(a(\bar{x})) \subseteq \mathcal I) \text{ and } (pre^-(a(\bar{x}))\cap \mathcal I = \emptyset$, where the $+$ and $-$ denote the positive and negative literals in the precondition. In words this means that all the true literals of the precondition must be in the state, and non of the false literals.
What is the latex symbol for $\cap$ ? #fc
\cap
What is the latex symbol for $\emptyset$ ? #fc
\emptyset
What is the latex symbol for $ \subseteq $ ? #fc
\subseteq
What is the result of applying action instance $a(\bar{x})$ to state $\mathcal I$? #fc
A new state
$$(\mathcal I ; \backslash eff^-(a(\bar{x}))) ; \cup ; eff^+(a(\bar{x}))$$. In words, it is the old state without the negative literals and with the new positive literals.
What is a stream in PDDLstream? #fc
A conditional generator $s(\bar{X})$ endowed with a declarative specification of any facts its inputs and outputs always satisfy.
What does $s.domain$ mean, for a stream $s$? #fc
The set of facts on the input parameters $s.input$ that specify the set of object tuples $\bar{x}$ for which $s(\bar{X})$ is defined. (such as "typing" information)
What does $s.certified$ mean? #fc
It is the set of certified redicates on both $s.input$ and $s.output$ that assert any facts that $\langle \bar{x}, \bar{y} \rangle$ satisfy.
(the properties the outputs are guarenteed to satisfy.