UNI-SEARCH-HEURISTIC : FLAGUNI-SEARCH-HEURISTIC is a flag or parameter.
Search strategy used to select the next node in the unification tree.
BREADTH-FIRST and DEPTH-FIRST are exactly as they sound;
BEST-FIRST takes whichever leaf node has the fewest free
variables (and is not already terminal).
All of these options work for UN90 (ms90-*, ms91-7, ms92-*);
BREADTH-FIRST and BEST-FIRST are the only options for UN88 (ms88, ms89,
UNI-SEARCH-HEURISTIC takes values of type SYMBOL.
It belongs to subjects UNIFICATION .
Its default value is BREADTH-FIRST
Its current value is BREADTH-FIRST.
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