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Lyubomir Ivanov (, born 7 October 1952 in Sofia ) is a scientist, non-governmental activist, and Antarctic explorer. He is a graduate of the St. Kliment Ohridski University of Sofia with M.S. degree in Mathematics in 1977, and earned his PhD from Sofia University in 1980 under the direction of Dimiter Skordev, with a dissertation entitled Iterative Operative Spaces.
 Lyubomir Ivanov, Sofia
Please list all entity pairs containing a certain relationship in the given options.Output format is "word1, word2; word3, word4". 
Option: place of death, place of birth, education degree, education institution 
Text: {0} 
Answer:
 Lyubomir Ivanov, Sofia