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He applied principles of fuzzy logic to improve its play between phases , and by July 1979 , BKG 9.8 was strong enough to play against the reigning world champion Luigi Villa .
 person: Luigi Villa
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 person: Luigi Villa