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JOURNALS // Zapiski Nauchnykh Seminarov POMI // Archive

Zap. Nauchn. Sem. POMI, 2019 Volume 481, Pages 74–86 (Mi znsl6779)

Limiting curves for the dyadic odometer

A. R. Minabutdinov

National Research University Higher School of Economics, Department of Mathematics, St. Petersburg, Russia

Abstract: A limiting curve of a stationary process in discrete time was defined by É. Janvresse, T. de la Rue, and Y. Velenik as the uniform limit of the functions
$$ t\mapsto \big(S(tl_n) - tS(l_n)\big)/R_n \in C([0, 1]), $$
where $S$ stands for the piecewise linear extension of the partial sum, $R_n := \sup |S(tl_n) - tS(l_n))|$, and $(l_n) = (l_n(\omega))$ is a suitable sequence of integers. We determine the limiting curves for the stationary sequence $(f\circ T^n(\omega))$ where $T$ is the dyadic odometer on $\{0,1\}^{\mathbb{N}}$ and
$$f((\omega_i)) = \sum\limits_{i\geq 0}\omega_iq^{i+1}$$
for $1/2 < |q| < 1.$ Namely, we prove that for a.e. $\omega$ there exists a sequence $(l_n(\omega))$ such that the limiting curve exists and is equal to $(-1)$ times the Tagaki–Landsberg function with parameter $1/2q.$ The result can be obtained as a corollary of a generalization of the Trollope–Delange formula to the $q$-weighted case.

Key words and phrases: limiting curves, weighted sum-of-binary-digits function, Takagi–Landsberg curve, $q$-analogue of the Trollope–Delange formula.

UDC: 517.987.5, 519.21

Received: 19.09.2019



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