[1] Czesław Bylinski. Functions and their basic properties. *Formalized Mathematics*, 1(**1**): 55-65, 1990.

[2] Czesław Bylinski. Functions from a set to a set. *Formalized Mathematics*, 1(**1**):153-164, 1990.

[3] Czesław Bylinski. Partial functions. *Formalized Mathematics*, 1(**2**):357-367, 1990.

[4] Czesław Bylinski. Some basic properties of sets. *Formalized Mathematics*, 1(**1**):47-53, 1990.

[5] Agata Darmochwał. Finite sets. *Formalized Mathematics*, 1(**1**):165-167, 1990.

[6] Adam Grabowski. Basic properties of rough sets and rough membership function. *Formalized**Mathematics*, 12(**1**):21-28, 2004.

[7] Adam Grabowski and Magdalena Jastrzebska. A note on a formal approach to rough operators. In Marcin S. Szczuka and Marzena Kryszkiewicz et al., editors, *Rough Sets**and Current Trends in Computing - 7th International Conference, RSCTC 2010, Warsaw,**Poland, June 28-30, 2010. Proceedings*, volume 6086 of *Lecture Notes in Computer**Science*, pages 307-316. Springer, 2010. doi:10.1007/978-3-642-13529-3 33. [Crossref]

[8] Artur Korniłowicz. Cartesian products of relations and relational structures. *Formalized**Mathematics*, 6(**1**):145-152, 1997.

[9] Beata Padlewska and Agata Darmochwał. Topological spaces and continuous functions. *Formalized Mathematics*, 1(**1**):223-230, 1990.

[10] Z. Pawlak. Rough sets. *International Journal of Parallel Programming*, 11:341-356, 1982. doi:10.1007/BF01001956. [Crossref]

[11] Konrad Raczkowski and Paweł Sadowski. Equivalence relations and classes of abstraction. *Formalized Mathematics*, 1(**3**):441-444, 1990.

[12] Andrzej Skowron and Jarosław Stepaniuk. Tolerance approximation spaces. *Fundamenta**Informaticae*, 27(2/3):245-253, 1996. doi:10.3233/FI-1996-272311. [Crossref]

[13] Andrzej Trybulec. Domains and their Cartesian products. *Formalized Mathematics*, 1(**1**): 115-122, 1990.

[14] Wojciech A. Trybulec and Grzegorz Bancerek. Kuratowski - Zorn lemma. *Formalized**Mathematics*, 1(**2**):387-393, 1990.

[15] Zinaida Trybulec. Properties of subsets. *Formalized Mathematics*, 1(**1**):67-71, 1990.

[16] Edmund Woronowicz. Relations and their basic properties. *Formalized Mathematics*, 1 (**1**):73-83, 1990.

[17] Mirosław Wysocki and Agata Darmochwał. Subsets of topological spaces. *Formalized**Mathematics*, 1(**1**):231-237, 1990.

[18] Y.Y. Yao. Two views of the theory of rough sets in finite universes. *International Journal**of Approximate Reasoning*, 15(4):291-317, 1996. doi:10.1016/S0888-613X(96)00071-0. [Crossref]

[19] William Zhu. Generalized rough sets based on relations. *Information Sciences*, 177: 4997-5011, 2007 [Web of Science]

## Comments (0)