Babai, György Elekes, Péter Komjáth, Imre Z. Ruzsa. At the beginning of the 1970s he got involved with the school reform movement called complex teaching of mathematics led by Tamás Varga. Pósa worked on the reform of secondary mathematics teaching, while he taught at Radnóti Miklós Secondary School from 1976 to 1980. From 1982 to 1989 he was a member of the Research Group on Mathematics Education led by János Surányi. From 1982 to 1991 he had two experimental classes at Eötvös József Secondary School. His teaching materials written at that time were tested in several classes, and based on these he and colleagues have written a textbook series for the four years of secondary school. Nevertheless, Pósa is best known for finding and teaching gifted students. Since 1988 he has been organizing his own week-end maths camps. There are several groups of 20-35 students, and each group has two or three camps a year. In a camp, students mostly work in groups of 2-4, but there are also plenary sessions where they discuss solutions, and sum up important thoughts. Students work on problems carefully built on each other. There are several topics running parallelly, and one topic spans several camps. The emphasis is on thinking, proving, and the connection between seemingly distant ideas. The camps are also an important scene of teacher training, as prospective teachers observe and help in the camps. Mathematical research He gave sufficient conditions for the existence of Hamiltonian circuit. He proved that a random graph on n vertices with cn log n edges almost surely contains a Hamiltonian circuit, thus affirming a conjecture of Erdős and Rényi (also proved by A. D. Korshunov). The result was later improved by Komlós and Szemerédi. With Erdős he proved the Erdős–Pósa theorem. Prizes, awards Prize for Children Support („Gyermekekért” díj), 1989 Beke Manó Prize I. degree by Bolyai János Mathematical Society, 1994 Officer’s Cross Order of Merit of the Republic of Hungary, 1998 Charles Simonyi Scholarship, 2000 MOL prize for Gifted Education (“Tehetséggondozásért” díj), 2008 Széchenyi Prize, 2011 Publications Pósa Lajos: A prímszámok egy tulajdonságáról, Matematikai Lapok, 11 (1960), 124-128. P. Erdős, L. Pósa: On the maximal number of disjoint circuits of a graph, Publ. Math. Debrecen, 9 (1962), 3-13. L. Pósa: A theorem concerning Hamilton lines, MTA Mat. Kut. Int. Közl. 7 (1962), 225-226. L. Pósa: On the circuits of finite graphs, MTA Mat. Kut. Int.