  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).
