On error sum functions formed by convergents of real numbers
J. Integer Seq. 14(8), Article 11.8.6, 14 p., electronic only (2011)
Summary
Summary: Let $ p_m/q_m$ denote the $ m$-th convergent $ (m\geq0)$ from the continued fraction expansion of some real number $ \alpha$. We continue our work on error sum functions defined by $ \mathcal{E}(\alpha) := \sum_{m\geq0} \vert q_m \alpha - p_m\vert$ and $ \mathcal{E}^*(\alpha) := \sum_{m\geq0} (q_m \alpha - p_m)$ by proving a new density result for the values of $ \mathcal{E}$ and $ \mathcal{E}^*$. Moreover, we study the function $ \mathcal{E}$ with respect to continuity and compute the integral $ \int_0^1 \mathcal{E}(\alpha) \,d\alpha$. We also consider generalized error sum functions for the approximation with algebraic numbers of bounded degrees in the sense of Mahler.
Mathematics Subject Classification
11J04, 11J70, 11B05, 11B39
Keywords/Phrases
continued fractions, convergents, approximation of real numbers, error terms, density