Faculty

Vladimir . DubovoyVladimir . Dubovoy Vladimir . Dubovoy Full professor of the department of pure mathematics, doctor of sciences in mathematics

Sergey  . FavorovSergey  . Favorov Sergey . Favorov Full professor of the department of pure mathematics, doctor of sciences in mathematics

Sergey . GefterSergey . Gefter Sergey . Gefter Associate professor of the department of pure mathematics, head of the department of pure mathematics, phd in mathematics

Vyacheslav . GordevskyyVyacheslav . Gordevskyy Vyacheslav . Gordevskyy Full professor of the department of pure mathematics, doctor of sciences in mathematics

Vladimir (Volodymyr) M. KadetsVladimir (Volodymyr) M. Kadets Vladimir (Volodymyr) M. Kadets Full professor of the department of pure mathematics, doctor of sciences in mathematics

Mariya . ShcherbinaMariya . Shcherbina Mariya . Shcherbina Professor of the department of pure mathematics

Dmitry . ShepelskyDmitry . Shepelsky Dmitry . Shepelsky Doctor of sciences in mathematics

Alexander L. YampolskyAlexander L. Yampolsky Alexander L. Yampolsky Professor of the department of pure mathematics, doctor of sciences in mathematics

Dmytry V. BolotovDmytry V. Bolotov Dmytry V. Bolotov Doctor of sciences in mathematics

Vasyl O. GorkavyyVasyl O. Gorkavyy Vasyl O. Gorkavyy Doctor of sciences in mathematics, associate professor

Alexander V. RezounenkoAlexander V. Rezounenko Alexander V. Rezounenko Professor of the department of pure mathematics, doctor of sciences in mathematics

Anna M. VishnyakovaAnna M. Vishnyakova Anna M. Vishnyakova Professor of the department of pure mathematics, doctor of sciences in mathematics

Tamara . FastovskaTamara . Fastovska Tamara . Fastovska Associate professor of the department of pure mathematics, phd in mathematics, associate professor

Nataliуa . GiryaNataliуa . Girya Nataliуa . Girya Associate professor of the department of pure mathematics, phd in mathematics

Oleksii . HukalovOleksii . Hukalov Oleksii . Hukalov Associate professor of the department of pure mathematics, phd in mathematics

Eugene . KarolinskyEugene . Karolinsky Eugene . Karolinsky Associate professor of the department of pure mathematics, phd in mathematics

Eugene V. PetrovEugene V. Petrov Eugene V. Petrov Phd in mathematics, senior lecturer

Aleksey . ShcherbinaAleksey . Shcherbina Aleksey . Shcherbina Phd in mathematics, senior lecturer

Olena O. ShugailoOlena O. Shugailo Olena O. Shugailo Phd in mathematics, senior lecturer

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Viktoria V. DavydovaViktoria V. Davydova Viktoria V. Davydova Engineer

Iryna V. KatsIryna V. Kats Iryna V. Kats Leading engineer

Thu Hien . NguyenThu Hien . Nguyen Thu Hien . Nguyen

Dmytro . SeliutinDmytro . Seliutin Dmytro . Seliutin

Olesia O. ZavarzinaOlesia O. Zavarzina Olesia O. Zavarzina Ph.d., associate professor

Sergey . Gefter

Associate professor of the department of pure mathematics, head of the department of pure mathematics, phd in mathematics

Link on external publications: google.scholar.

List of selected publications

Sergey Gefter, Aleksey Piven Entire solutions of one linear implicit differential-difference equation in Banach spaces // Ukrains’ kyi Matematychnyi Zhurnal, 2018, (70), #8, 1044-1057,

We establish the existence and uniqueness conditions for the solution for the initial problem in the classes of entire functions of exponential type. Closed linear operators act on Banach spaces and can be degenerate. We also present an example of application of abstract results to partial differential equations.

Sergey Gefter, Aleksey Piven Implicit linear difference equation in Frechet spaces // Dopov. Nac. akad. nauk Ukr. , 2017, 6:3-8,

An criterion of the existence and the uniqueness for a solution of the implicit linear difference equation Axn+1+Bxn=gn, where A and B are continuous operators, which act on Frechet spaces, is proved. Explicit formulas for the solution of this equation are found. For the case of Banach spaces, the results are specified.

Keywords: Frechet space, implicit difference equation

S. L. Gefter, A. L. Piven’ Initial problem for a nonhomogeneous linear differential-difference equation in a Banach space for a class of exponential type entire functions // European Journal of Mathematics, 2020. Vol. 6. P. 197-207,

We prove the existence and uniqueness of a solution to a one-point initial problem for the nonhomogeneous linear differential-difference equation u′(z)=Au(z+h)+f(z), z∈C, in some classes of exponential type entire vector-valued functions. The obtained formula for the unique solution can be considered as a generalization of the classical Cauchy formula for a solution to the nonhomogeneous linear differential equation.

S.L. Gefter, V. V. Martseniuk & A. L. Piven’ INTEGER SOLUTIONS OF A SECOND ORDER IMPLICIT LINEAR DIFFERENCE EQUATION // Bukovinian Mathematical Journal. , 6, 3-4 (Mar. 2019).,

We consider the following second order linear difference equation cx_{n+2}\;=\;bx_{n+1}+ax_n-f_n,\;n=0,1,2,... where a,b,c i f_n be integers (n = 0,1,2,...). If c = ±1 then we have the explicit equation and, obviously, for any initial data x0,x1 ∈ Z this equation has a unique integer solution. In what follows we assume c ≠ ±1 and b or a is not divisible by c. Under this assumption the equation is called implicit over the ring Z. If the equation is considered over some field (for example, the field of real numbers) then the concept of the implicit equation makes no sense. In this case the theory of linear difference equations is well developed. Recently the first order implicit difference equations were studied over Z.

Keywords: LINEAR DIFFERENCE EQUATION