239575
A Z-number is a real number x such that the fractional part s are less than 1/2 for all natural numbers n. Kurt Mahler conjectured in 1968 that there are no Z-numbers .
 Kurt Mahler
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 Kurt Mahler