“…The work presented here relates to incremental or on-line concept learning, which has recently received considerable attention among theoreticians (e.g., Angluin, 1988;Maass, 1991;Helmbold, Littlestone, & Long, 1992) as well as practitioners (e.g., Schlimmer & Granger, 1986;Langley, Gennari, & Iba, 1987;Kilander & Jansson, 1993;Kubat, 1989Kubat, , 1993Salganicoff, 1993a;Widmer & Kubat, 1993), The principal task is to learn a concept incrementally by processing labeled training examples one at a time. From another point of view, the problem may be seen as minimizing the total number of erroneous classifications in a feedback system: a stream of objects are classified, one by one, as positive or negative instances of a concept, and immediately afterwards the correct answer is received.…”