.TH search 9 "September 7, 1994"
.SH NAME
Searching the subsumption lattice with
.I Progol.
.SH DESCRIPTION
When constructing hypothesis clauses consistent with the
examples
.I
Progol
does a general-to-specific search based on theta-subsumption.
Unlike many other ILP systems, the lattice searched by Progol
is bounded on top and bottom. The top of the lattice is the
empty clause, and the bottom is tje most-specific inverse
resolvent for an example, within the constraints of the
mode language.
.I
Progol
thus does "Mode-directed Inverse Resolution" (MDIR). 
Between these two points in the subsumption lattice,
.I
Progol
does a best-first search using an approximate compression
measure. The compression of any clause found by
.I
Progol
is calculated as P - N - C, where P = number of positive
examples covered by the clause, N = number of negative
examples covered by the clause, and C = number of literals
in the clause.
.SH "SEE ALSO"