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Philosophers such as David K. Lewis and David Armstrong developed elaborate theories on a range of topics such as universals , causation , possibility and necessity and abstract objects .
 person: David K. Lewis; person: David Armstrong
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: media, plant, vehicle, astronomical object, time, disease, animal, location, person, organization, mythical figure, food, biology, geographical phenomenon, instrument, event 
Text: {0} 
 Entities: David K. Lewis, David Armstrong 
Answer:
 person: David K. Lewis; person: David Armstrong