Ivan Sleszynski graduated from Odessa University in 1875. He then travelled to Germany where he studied under Weierstrass in Berlin, receiving his doctorate in 1882. Returning to Odessa, he became professor of mathematics there from 1883 to 1909.
Sleszynski went to Poland where he was appointed to the University of Krakóv in 1911. He continued to work at Krakóv until he retired in 1924.
Sleszynski's main work was on continued fractions, least squares and axiomatic proof theory based on mathematical logic.
In 1898 A Pringsheim
proved that the condition |bn|
|an| + 1,
an
0,
n
1, ensures the convergence
of the continued fraction
K(an/bn), where
an and bn are complex numbers;
a result known as the Pringsheim
criterion. W J Thron states in [2] that this result was established ten years
earlier by Sleszynski. Thron demonstrates that Pringsheim
was aware of Sleszynski's work, though Pringsheim
himself claims that he only became aware of Sleszynski after his article was
completed.
Six papers by Sleszynski on continued fractions are discussed
in [2] where a complete bibliography of Sleszynski's mathematical papers is
given. His work on continued fractions is also discussed in [1].