Stieltjes
Stieltjes refers to several concepts related to the work of Dutch mathematician Thomas Joannes Stieltjes. Most prominently, it is associated with the Stieltjes integral, a generalization of the Riemann integral. In the Stieltjes integral, the increment of the integration variable is replaced by the increment of a second function, often denoted as $\alpha(x)$. This allows for integration with respect to a more general function than just $x$, enabling the integration of functions with discontinuities or with respect to measures.
The Stieltjes integral is denoted as $\int_a^b f(x) \, d\alpha(x)$. If $\alpha(x) = x$, the Stieltjes integral reduces
Another important concept is the Stieltjes constants, denoted by $\gamma_n$. These are a sequence of real numbers