David Gilbert is considered one of the most influential mathematicians of the XIX and XX centuries.

###### Childhood and youth

David Gilbert was born on January 23, 1862 in Koenigsberg, Prussia. Despite the fact that his father was a respected city judge, and his mother was fond of philosophy and astronomy, his family had average prosperity. It is believed that his mother was carried away by simple numbers and forms and, perhaps, this was one of the reasons why Hilbert achieved excellent results in mathematics already at a young age. Gilbert also felt a desire for languages, but left his interest in them to fully engage in subjects that fascinated him most – mathematics and science.

###### Education

Gilbert studied at the University of Königsberg under the leadership of Heinrich Weber, the only mathematics professor at the time, with a doctorate. To attend additional lectures on differential equations, Hilbert Semester studied at another university in Gilderberg. Later, under the guidance of Ferdinand Lindemann, Hilbert passed an oral examination, and also submitted his thesis on invariants in 1845. The following year he received a doctorate in philosophy from the University of Königsberg. Hurwitz, his friend, who influenced his mathematical achievements, advised Hilbert to go to learn from the well-known mathematicians of Europe. Following this advice, Gilbert met Felix Klein in Leipzig, Henri Poincare in Paris and Leopold Kronecker in Berlin and realized that their ideas did not inspire him.

###### Career

Gilbert was offered a teaching position at the University of GцTttingen, but he refused, finding the salary low. His earnings depended on the money that the students paid for their education. But because of the number of lecturers reaching eleven, often the teacher-student ratio turned out to be 1: 1. When Gilbert realized that he would not achieve anything promising at this place of work in order to overcome boredom, he went on a second study tour. Since the result of the first trip did not satisfy him, the second time he planned the trip in advance, because he wanted to meet with twenty one of the greatest mathematicians. And during the second trip he had the opportunity to meet with Paul Gordan, Klein, Kronecker, Weierstrass and Schwartz. Gilbert was completely satisfied with the trip, and after returning to Koenigsberg, began work on the solution of the mathematical problem that Paul Gordan suggested, to the proof

of a finite basis. After months of hard work, Gilbert thought he had come to the right decision of the problem. He was sure that he made a mathematical breakthrough, and therefore the joy of the opening overwhelmed him.

But, unfortunately, his solution did not impress the eminent mathematicians, and Gordan did not want to accept Hilbert’s evidence in any way. But one outstanding mathematician, Felix Klein, reading the results, was pleased with the proposed solution and invited Hilbert to the University of GцTttingen for further education. This is what allowed Hilbert to find constructive evidence for the solution of the Gordan problem in 1892, and this time the decision suited the author of the problem.

###### Late years

After his scientific breakthrough, in the personal life of David Hilbert, there have also been significant changes for the better. After he became a professor with a doctorate at the Swiss Higher Technical School in Zurich, he also received the post of associate professor at the University of Koenigsberg. A few weeks later, the German Mathematical Society appointed Hilbert responsible for carrying out a comprehensive comprehensive study of number theory. Such an honor he was awarded for being able to find the most truthful proof of the transcendence of the numbers “π” and “e”. Together with his friend, mathematician Minkowski, he worked on the theory of numbers; Minkowski dealt with geometric research questions, while Hilbert focused on algebraic questions. Minkowski never managed to complete his part of the study. One of those,

Before the publication of the book on this study, Gilbert received a telegram from Felix Klein, in which he was informed of the proposal to take the place of a professor at the University of Göttingen. It was from this university that such well-known mathematicians as Karl Friedrich Gauss, a well-known scientist engaged in number theory, came out. At that time, the university had a brilliant mathematical community, which, according to Klein, would have been added to Gilbert’s fatherly way.

Basically Hilbert dealt with the theory of invariants, and his proof of the “Gordan problem” made him known among other mathematicians.

###### Personal life

David Gilbert married his second cousin Kete Erosh on October 12, 1892. And in 1893 their son was born, Franz. After receiving an invitation from Klein, Gilbert decided to stay with his family in Göttingen.

###### Contribution to science

David Gilbert greatly influenced the algebra and geometry known to us today. One of the prolific mathematicians – Weyl – highly appreciated the work of Hilbert on the theory of invariants, and also spoke of Hilbert’s allegiance to the subject he was studying. One of his important works is the “90th theorem” – a work in which the finite cyclic Galois extension is discussed. This work has become one of the most significant in his long career.

###### The last years of life and death

In 1902-1939, David Gilbert was the editor of one of the leading mathematical journals. In 1930, at the age of 68, he was forced to leave the university. This was due to the strict laws imposed by Adolf Hitler, which forbade Jews to teach. Thus, the Nazis put an end to the mathematical career of Hilbert. On February 14, 1943, Gilbert died of frustration and other health problems. His funeral was attended by less than ten people, most of whom were his mathematicians. And only six months later the world learned of his death.