The numbers that are part of active arc names are not especially significant. All that matters is that different arcs have different names. ARC10 in the first list of active-arcs arise because of an idiosyncrasy of the program used to produce the parses. When you do these exercises yourself, you would naturally call these arcs ARC1, ARC2, ARC3, and that is fine. For solution, see lecture notes .
Operators transform one state into another.
A sentential form is a string derived from S using the phrasal and lexical rules of a grammar, and which still contains at least one non-terminal symbol. Give an example of a predicate operator in the logical form language. A daemon is a procedure which is triggered when a slot in a frame is accessed in a certain way. Conflict resolution occurs when a number of rules are all eligible to fire. A strategy is then required to decide which of the eligible rules should be used.