Valentina Borok

In 1994, Borok became severely ill but because there was no necessary medical attention available in Ukraine, she had to move to Haifa, Israel, where she died at the age of 72 in 2004. Both of her children, Michail Zhitomirskii and Svetlana Jitomirskaya, became research mathematicians.

Starting in the early 1970s, Borok opened a school for the study of the general theory of Partial Differential Equations in Kharkiv State University. Many of her papers helped the development of the theory of local and non-local boundary value problems in infinite layers for systems of Partial differential equations. One of her earliest works includes results on the uniqueness and well-posedness of the solutions of the Cauchy problem. Most of her works were concentrated in the area of Partial differential equations along with functional-differential equations. even to this day many of her works are being cited.

In the early 1960s Borok worked on the stability for partial differential equations well-posed. Her other works at this time were on the parabolic systems degenerating at infinity and on the dependence of classes of uniqueness on the transformations of the spatial argument. most of her works during this period of time were mostly joint works with her husband Yakov Zhitomirskii.

And during the period of the late 1960s, Borok began her series of papers that laid the foundations for the theory of local and non-local boundary value problems in infinite layers for systems of partial differential equations. The results of her studies included the construction of maximal classes of uniqueness and well-posedness, Phragmen- Lindelöf type theorems, and the study of asymptotic properties and stability of solutions of boundary-value problems in infinite layers.

Valentina Borok had a talent for math even in her high school years. So in 1949, with the advice of her high school teachers Borok started to study Mathematics at Kiev State University. There she met Yakov Zhitomirskii, who would be her husband until her death. During her stay at Kiev State University, Borok, along with her future husband, started her research in the field of mathematics under the supervision of the mathematics department supervisor, Georgii Shilov. Her undergraduate thesis on distribution theory and the applications to the theory of systems of linear partial differential equations was found to be extraordinary and was published in a top Russian journal. This thesis was later selected in 1957 to be part of the first volumes of American Mathematical Society translations. In 1954, Borok graduated from Kiev State University and moved to Moscow State University in order to receive her graduate degree. In 1957, she received her PhD for her thesis On Systems of Linear Partial Differential Equations with Constant Coefficients. The information about the system of Linear Partial Differential equations with constant coefficient was publicized in the annals of mathematics. She later published more papers from 1954 to 1959, which contained a range of inverse theorems that allowed partial differential equations to be characterized by certain properties of their solutions. “In the same period she obtained formula that made it possible to compute in simple algebraic terms the numerical parameters that determine classes of uniqueness and well-posed of the Cauchy problem for systems of linear partial differential equations with constant coefficients". In 1960, she moved to Kharkiv State University, where she stayed until 1994. In 1970, Borok became a full professor and from 1983 to 1994, she was the Chair of the analysis department.

Valentina Mikhailovna Borok (9 July 1931 – 4 February 2004) was a Soviet Ukrainian mathematician. She is mainly known for her work on partial differential equations.

Borok was born on July 9, 1931 in Kharkiv in Ukraine (then USSR), into a Jewish family. Her father, Michail Borok, was a chemist, scientist and an expert in material science. Her mother, Bella Sigal, was a well-known economist. Because of her mothers' high position at the ministry of Economics, Valentina Borok had a privileged early childhood. However, because of the political situation, her mother voluntarily resigned in 1937 and took a lower position, presumably because she knew she couldn't possibly have been spared the repressions of the late 1930s. This possibly helped the Borok family survive World War II.