84867
In it , he made major advances in the direction of a solution to Gudkov 's conjecture , by finding a connection between it and four-dimensional topology .
 person: Gudkov
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: location, person, organization 
Text: {0} 
 Entities: Gudkov 
Answer:
 person: Gudkov