In 2015, Goebel and Bolibok defined the initial trend coefficient of a mapping and the class of initially nonexpansive mappings. They proved that the fixed point property for nonexpansive mappings implies the fixed point property for initially nonexpansive mappings. We generalize the above concepts and prove an analogous fixed point theorem. We also study the initial trend coefficient more deeply.

We study the so-called inverse problem. Namely, given a prescribed skew-symmetric Ricci tensor we find (locally) a respective linear connection.

In this paper we introduce generalized Mersenne numbers. We shall present some of their interpretations and matrix generators which are very useful for determining identities.

Some new inequalities of Hermite-Hadamard type for GA-convex functions defined on positive intervals are given. Refinements and weighted version of known inequalities are provided. Some applications for special means are also obtained.

In the paper, we present Helena Rasiowa's scientific personality emphasizing the period WWII and beginning of her professional activity after 1945.

The paper deals with the history of Polish mathematical societies since 1917, when the Mathematical Society in Lvov was founded. In the second half of the 19th century there appeared first national mathematical societies in Russia, France, United Kindom, Italy, United States, Germany. In Poland, partitioned then by neighbour powers (Russia, Prussia, Austria) whose policy was to deny Polish national...

Based on a deep and extensive study of various "funds" of the Archive of Charles University, the Archive of the Czech Technical University in Prague, the National Archive of the Czech Republic, the Archive of the Academy of Sciences of the Czech Republic, the Prague City Archives and the State Archive of the German Republic, we are going to evaluate professional activities and personal life...

This article is the first part of research devoted to the inception and formation of mathematics history as a separate science in Russia. Its elements began intensively emerging in the epoch of Peter the Great and underwent several developmental stages. This work outlines five stages that Russian scientists went through while molding elements of studies in the history of mathematics into a science...

Poland in the years 1918–1939 became one of the main centres of mathematical logic in the entire Word. This paper describes the rise of this field in Poland, Polish logical circles, organizations, journals and the main achievements of Polish logicians.

The Samuel Dickstein's price is awarded for outstanding achievements in the field of mathematical education, popularization and history of mathematics. It was established in 1978 and the first one recognized by it was Stefan Straszewicz. In 2016, the Samuel Dicstein main PTM award was honored with Professor Lech Maligranda from the Technical University of Lule {\ aa} (Sweden) for outstanding achievements...

In this note, results of the Conference ”Poděbrady 2018” are discussed.

This article is devoted to the Seminar on Applied Mathematics, conducted in 1948-1960 by Professor Hugo Steinhaus in Wroclaw. It is based on the protocols of this Seminar so far not discussed anywhere. Many facts related to Professor Hugo Steinhaus can be found easily in the literature, also in the diary of the professor \emph{Mathematician for all seasons--recollections and notes.} (2016). Steinhaus...

We present a subsequent volume, 12 (2018), of the Series VI of Roczniki Polskiego Towarzystwa Matematycznego – “Antiquitates Mathematicae”, a journal devoted to history of mathematics. In it, we offer 10 articles (6 in English, 4 in Polish), a profile of Professor Lech Maligranda-the recipient of the Samuel Dickstein Main Prize of the Polish Mathematical Society for the year 2016, as well as a report...

An analysis of the mathematical contributions of Juliusz Schauder through the writings of contemporary mathematicians, and in particular Leray, Hadamard, Banach, Randolph, Federer, Lorentz, Ladyzhenskaya, Ural'tseva, Orlicz, G\aa rding and Pietsch.

Tomasz Franciszek Schreiber, a young Polish mathematician, passed away on December 1, 2010. Since 2009 he was a professor at the Department of Probability Theory and Stochastic Analysis at the Faculty of Mathematics and Computer Science at the Nicolaus Copernicus University (NCU) in Toruń.

Jan Ptaszycki was a Polish mathematician working in St. Petersburg in the period 1876--1912. In Poland, he is forgotten, and in Russia considered generally for Russian mathematician, known there as Ivan Lvovich Ptaszycki. There is no article about it on Polish {\it Wikipedia}, while there are three articles in Russian. In historical-mathematical Russian literature, depending on the author, it is reported...