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However , in the pure Gauss–Bonnet gravity ( a modification to general relativity involving extra spatial dimensions which is sometimes studied in the context of brane cosmology ) exotic matter is not needed in order for wormholes to exist - they can exist even with no matter .
 person: Gauss–Bonnet
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: Gauss–Bonnet 
Answer:
 person: Gauss–Bonnet