Jarkko Kari

Jarkko J. Kari is a Finnish mathematician and computer scientist, known for his contributions to the theory of Wang tiles and cellular automata.

[1] Kari received his Ph.D. in 1990 from the University of Turku; his dissertation, supervised by Arto Salomaa.

[4] The same approach was later shown to lead to aperiodic sets of 13 tiles, the minimum known.

[5] Kari has also shown that the Wang tiling problem remains undecidable in the hyperbolic plane,[6] and has discovered sets of Wang tiles with additional mathematical properties.

In particular, in his thesis research, he showed that it is undecidable to determine whether a given cellular automaton rule in two or more dimensions is reversible.