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In mathematics , the Serre spectral sequence ( sometimes Leray-Serre spectral sequence to acknowledge earlier work of Jean Leray in the Leray spectral sequence ) is an important tool in algebraic topology .
 Serre, Jean Leray, Leray
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 Serre, Jean Leray, Leray