Viliam Geffert

Viliam Geffert
Viliam Geffert
Born	1955 (age 68–69)
Alma mater	P. J. Šafárik University, Comenius University
Known for	state complexity, small-space complexity
	Scientific career
Fields	Automata theory, computational complexity
Institutions	P. J. Šafárik University

Viliam Geffert (born 1955) is a Slovak theoretical computer scientist known for his contributions to 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 edit

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.

^ Geffert, Viliam (1993). "Tally Versions of the Savitch and Immerman–Szelepcsényi Theorems for Sublogarithmic Space". SIAM Journal on Computing. 22 (1): 102–113. doi:10.1137/0222009. ISSN 0097-5397.
^ Geffert, Viliam; Mereghetti, Carlo; Pighizzini, Giovanni (1998). "Sublogarithmic Bounds on Space and Reversals". SIAM Journal on Computing. 28 (1): 325–340. doi:10.1137/S0097539796301306. hdl:2434/178756. ISSN 0097-5397. S2CID 37853723.
^ Geffert, Viliam (2012). "An alternating hierarchy for finite automata". Theoretical Computer Science. 445: 1–24. doi:10.1016/j.tcs.2012.04.044. ISSN 0304-3975.
^ Geffert, Viliam; Mereghetti, Carlo; Pighizzini, Giovanni (2007). "Complementing two-way finite automata". Information and Computation. 205 (8): 1173–1187. doi:10.1016/j.ic.2007.01.008. ISSN 0890-5401.
^ Franceschini, Gianni; Geffert, Viliam (2005). "An in-place sorting with O(nlog n) comparisons and O(n) moves". Journal of the ACM. 52 (4): 515–537. arXiv:cs/0305005. doi:10.1145/1082036.1082037. ISSN 0004-5411. S2CID 2148080.
^ Geffert, Viliam; Gajdoš, Jozef (2011). "In-Place Sorting". SOFSEM 2011: Theory and Practice of Computer Science. Lecture Notes in Computer Science. Vol. 6543. pp. 248–259. Bibcode:2011LNCS.6543..248G. doi:10.1007/978-3-642-18381-2_21. ISBN 978-3-642-18380-5. ISSN 0302-9743.