7884
In geometric graph theory , the " Hadwiger–Nelson problem " , named after Hugo Hadwiger and Edward Nelson , asks for the minimum number of colors required to color the plane such that no two points at distance 1 from each other have the same color .
 person: Hugo Hadwiger; person: Edward Nelson
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: Hugo Hadwiger; person: Edward Nelson