On one class of functions with complicated local structure that the   solutions of infinite systems of functional equations (On one application of   infinite systems of functional equations in the functions theory)
  The article is devoted to investigation of applications of infinite systems of functional equations for modeling of functions with complicated local structure, that are defined in terms of the nega-$\tilde Q$-representation. The infinite system of functional equations $$ f\left(\hat \varphi^k(x)\right)=\tilde \beta_{i_{k+1},k+1}+\tilde p_{i_{k+1},k+1}f\left(\hat \varphi^{k+1}(x)\right), $$ where $k=0,1,...$, $\hat \varphi$ is a shift operator of the $\tilde Q$-expansion, $x=\Delta^{-\tilde Q} _{i_1(x)i_2(x)...i_n(x)...}$, are investigated. It is proved, that the system has the unique solution in the class of determined and bounded on $[0;1]$ functions and continuity of the solution. His analytical presentation is founded. Conditions of its monotonicity and nonmonotonicity, differential, integral properties are studied. Conditions under which the solution of the functional equations system is a distribution function of random variable $\eta=\Delta^{\tilde Q} _{\xi_1\xi_2...\xi_n...}$ with independent $\tilde Q$-symbols are discovered.   The results of the article was represented in Fourth all-Ukrainian Scientific Conference of Young Scientists on Mathematics and Physics, Kyiv, April 23-25, 2015 (https://www.researchgate.net/publication/301765100).   The investigation was represented at the seminar on fractal analysis of Institute of Mathematics of the National Academy of Sciences of Ukraine on, October 30, 2014 (http://www.imath.kiev.ua/events/index.php?seminarId=21&archiv=1). 
Symon Serbenyuk
math.CA