András Gyárfás

{{short description|Hungarian mathematician}}

András Gyárfás (born 1945) is a Hungarian mathematician who specializes in the study of graph theory. He is famous for two conjectures:

• Together with Paul Erdős he conjectured what is now called the Erdős–Gyárfás conjecture which states that any graph with minimum degree 3 contains a cycle whose length is a power of two.
• He and David Sumner independently formulated the Gyárfás–Sumner conjecture{{citation

| last = Gyárfás | first = A. | authorlink = András Gyárfás

| contribution = On Ramsey covering-numbers

| location = Amsterdam

| mr = 0382051

| pages = 801–816

| publisher = North-Holland

| series = Colloq. Math. Soc. János Bolyai

| title = Infinite and finite sets (Colloq., Keszthely, 1973; dedicated to P. Erdős on his 60th birthday), Vol. II

| volume = 10

| year = 1975}} according to which, for every tree T, the T-free graphs are χ-bounded.

Gyárfás began working as a researcher for the Computer and Automation Research Institute of the Hungarian Academy of Sciences in 1968. He earned a candidate degree in 1980, and a doctorate (Dr. Math. Sci.) in 1992. He won the Géza Grünwald Commemorative Prize for young researchers of the János Bolyai Mathematical Society in 1978.[http://wwwold.sztaki.hu/sztaki/ake/applmath/discret/gyarfas_cv.jhtml Gyárfás's CV], retrieved 2016-07-12.{{Cite web |title=Non-math in Hungarian |url=https://www.renyi.hu/~gyarfas/index_files/non_math_in_hungarian.htm |work=www.renyi.hu |accessdate=2020-12-16}} He was co-author with Paul Erdős on 15 papers, and thus has Erdős number one.{{cite journal | last1=Erdős | first1=Paul | last2=Gyárfás | first2=András | last3=Kohayakawa | first3=Yoshiharu | title=The size of the largest bipartite subgraphs | journal=Discrete Mathematics | publisher=Elsevier BV | volume=177 | issue=1–3 | year=1997 | issn=0012-365X | doi=10.1016/s0012-365x(97)00004-6 | pages=267–271| doi-access= }}