Hasan Abdullayev (also spelled as Gasan Mamed Bagir ogly Abdullaev; Azerbaijani: Həsən Məmmədbağır oğlu Abdullayev; Russian: Гасан Мамед Багир оглы Абдуллаев; August 20, 1918 – September 1, 1993) was a leading Soviet and Azerbaijani physicist, scientist and public official, who served as President of the National Academy of Sciences of the Azerbaijan SSR. He was a Doctor of Sciences in physics and mathematics, Professor of physics and mathematics, Director of the Institute of Mathematics and Physics of the National Academy of Sciences of the Azerbaijan SSR, full Academician of the National Academy of Sciences of the Azerbaijan SSR, corresponding member of the Soviet Academy of Sciences and Russian Academy of Sciences, and in 1970-1983 was the longest-serving President of the National Acade