Information: - A mathematical problem is a problem that is amenable to being represented, analyzed, and possibly solved, with the methods of mathematics. This can be a real-world problem, such as computing the orbits of the planets in the solar system, or a problem of a more abstract nature, such as Hilbert's problems.<br> It can also be a problem referring to the nature of mathematics itself, such as Russell's Paradox. - Ivan Vidav ( January 17 , 1918 -- October 6 , 2015 ) was a Slovenian mathematician . Ivan Vidav was born in Opine near Trieste ( Slovenian Trst ) , Italy . He was Josip Plemelj 's student . Vidav got his Ph.D. under Plemelj 's advisory in 1941 at the University of Ljubljana with a dissertation Kleinovi teoremi v teoriji linearnih diferencialnih enab ( Klein 's theorems in the theory of linear differential equations ) . Vidav 's main research interest were differential equations , functional analysis and algebra . He was a regular member of Slovenian Academy of Sciences and Arts . He was awarded the Preseren Award . From 1988 he was an honourable member of the Society of Mathematicians , Physicists and Astronomers of Slovenia ( DMFA ) . - A mathematician is someone who uses an extensive knowledge of mathematics in his/her work, typically to solve mathematical problems. - Mathematics (from Greek "mathma", knowledge, study, learning) is the study of topics such as quantity (numbers), structure, space, and change. There is a range of views among mathematicians and philosophers as to the exact scope and definition of mathematics. After reading the paragraphs above, choose the best answer for the entity that related to 'ivan vidav' with the relationship of 'field of work'. Choices: - mathematician - mathematics - nature
The answer to this question is:
mathematics