39005
The Poincaré conjecture claims that if such a space has the additional property that each loop in the space can be continuously tightened to a point , then it is necessarily a three-dimensional sphere .
 Poincaré
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 Poincaré