Viliam Geffert Explained

Viliam Geffert
Field:	Automata theory, computational complexity
Work Institution:	P. J. Šafárik University
Alma Mater:	P. J. Šafárik University, Comenius University
Known For:	state complexity, small-space complexity

Viliam Geffert (born 1955) is a Slovaktheoretical computer scientistknown for his contributionsto the computational complexity theory in sublogarithmic space^{[1] [2]} and to the state complexity of two-way finite automata.^{[3] [4]} He has also developed new in-place sorting algorithms.^{[5] [6]} He is a professor and the head of the computer science department at the P. J. Šafárik University in Košice.

Biography

Geffert did his undergraduate studies at the P. J. Šafárik University, graduating in 1979. He earned his PhD degree in 1988 from the Comenius University in Bratislava. Since 2003, he is a full professor of the P. J. Šafárik University.

Notes and References

1. Geffert. Viliam. Tally Versions of the Savitch and Immerman–Szelepcsényi Theorems for Sublogarithmic Space. SIAM Journal on Computing. 22. 1. 1993. 102–113. 0097-5397. 10.1137/0222009.
2. Geffert. Viliam. Mereghetti. Carlo. Pighizzini. Giovanni. Sublogarithmic Bounds on Space and Reversals. SIAM Journal on Computing. 28. 1. 1998. 325–340. 0097-5397. 10.1137/S0097539796301306. 2434/178756. 37853723 . free.
3. Geffert. Viliam. An alternating hierarchy for finite automata. Theoretical Computer Science. 445. 2012. 1–24. 0304-3975. 10.1016/j.tcs.2012.04.044. free.
4. Geffert. Viliam. Mereghetti. Carlo. Pighizzini. Giovanni. Complementing two-way finite automata. Information and Computation. 205. 8. 2007. 1173–1187. 0890-5401. 10.1016/j.ic.2007.01.008. free.
5. Franceschini. Gianni. Geffert. Viliam. An in-place sorting with O(nlog n) comparisons and O(n) moves. Journal of the ACM. 52. 4. 2005. 515–537. 0004-5411. 10.1145/1082036.1082037. cs/0305005. 2148080.
6. Book: Geffert. Viliam. Gajdoš. Jozef. SOFSEM 2011: Theory and Practice of Computer Science. In-Place Sorting. Lecture Notes in Computer Science. 6543. 2011. 248–259. 0302-9743. 10.1007/978-3-642-18381-2_21. 2011LNCS.6543..248G. 978-3-642-18380-5.