Christos Papakyriakopoulos

Christos Dimitriou Papakyriakopoulos (/ˌpæpəˌkɪriəˈkɑːpəloʊs/), commonly known as Papa (Greek: Χρήστος Δημητρίου Παπακυριακόπουλος [papakirʝaˈkopulos]; June 29, 1914 – June 29, 1976), was a Greek mathematician specializing in geometric topology.

Papakyriakopoulos was born in Chalandri, then in the Municipality of Athens, now in North Athens.

Papakyriakopoulos worked in isolation at Athens Polytechnic as research assistant to Professor Nicolaus Kritikos. But he was enrolled as research student at Athens University being awarded a Ph.D. in 1943 on the recommendation of Carathéodory. In 1948, he was invited by Ralph Fox to come as his guest at the Princeton mathematics department because Fox had been impressed by a letter from Papakyriakopoulos that purported to prove Dehn's lemma. The proof, as it turned out, was faulty but Fox's sponsorship would continue for many years and enabled Papakyriakopoulos to work on his mathematics without concern of financial support.

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