Functions of ultraexponential and infralogarithm types and general solution of the Abel functional equation

We propose generalized forms of ultraexponential and infralogarithm functions introduced and studied by the author earlier and present two classes of special functions, namely, ultraexponential and infralogarithm $f$-type functions. As a result of present investigation, we obtain general solution of...

Повний опис

Збережено в:
Бібліографічні деталі
Дата:2011
Автори: Нооshmаnd, М. Н., Хушманд, М. Х.
Формат: Стаття
Мова:Англійська
Опубліковано: Institute of Mathematics, NAS of Ukraine 2011
Онлайн доступ:https://umj.imath.kiev.ua/index.php/umj/article/view/2716
Теги: Додати тег
Немає тегів, Будьте першим, хто поставить тег для цього запису!
Назва журналу:Ukrains’kyi Matematychnyi Zhurnal
Завантажити файл: Pdf

Репозитарії

Ukrains’kyi Matematychnyi Zhurnal
Опис
Резюме:We propose generalized forms of ultraexponential and infralogarithm functions introduced and studied by the author earlier and present two classes of special functions, namely, ultraexponential and infralogarithm $f$-type functions. As a result of present investigation, we obtain general solution of the Abel equation $\alpha (f(x)) = \alpha (x) + 1$ under some conditions on a real function $f$ and prove a new completely different uniqueness theorem for the Abel equation stating that the infralogarithm $f$-type function is its unique solution. We also show that the infralogarithm $f$-type function is an essentially unique solution of the Abel equation. Similar theorems are proved for the ultraexponential $f$-type functions and their functional equation $\beta(x) = f(\beta(x − 1))$ which can be considered as dual to the Abel equation. We also solve certain problem being unsolved before, study some properties of two considered functional equations and some relations between them.