Abstract
We show that certain representations of graphs by operators on Hilbert space have uses in signal processing and in symbolic dynamics. Our main result is that graphs built on automata have fractal characteristics. We make this precise with the use of Representation Theory and of Spectral Theory of a certain family of Hecke operators. Let G be a directed graph. We begin by building the graph groupoid \(\Bbb{G}\) induced by G, and representations of \(\Bbb{G}\) . Our main application is to the groupoids defined from automata. By assigning weights to the edges of a fixed graph G, we give conditions for \(\Bbb{G}\) to acquire fractal-like properties, and hence we can have fractaloids or G-fractals. Our standing assumption on G is that it is locally finite and connected, and our labeling of G is determined by the “out-degrees of vertices”. From our labeling, we arrive at a family of Hecke-type operators whose spectrum is computed. As applications, we are able to build representations by operators on Hilbert spaces (including the Hecke operators); and we further show that automata built on a finite alphabet generate fractaloids. Our Hecke-type operators, or labeling operators, come from an amalgamated free probability construction, and we compute the corresponding amalgamated free moments. We show that the free moments are completely determined by certain scalar-valued functions.
Similar content being viewed by others
References
Balacheff, F.: Volume entropy, systole and stable norm on graphs. Preprint arXiv:math.MG/0411578v1 (2004)
Bartholdi, L., Grigorchuk, R., Nekrashevych, V.: From fractal groups to fractal sets. Preprint arXiv:math.GR/0202001v4 (2002)
Bell, G.C.: Growth of the asymptotic dimension function for groups. Preprint (2005)
Cho, I.: The moments of certain perturbed operators of the radial operator of the free group factor L(F N ). JAA 5(3), 137–165 (2007)
Cho, I.: Characterization of free blocks of a right graph von Neumann algebra. To be appeared in Complex Anal. Oper. Theory (2007)
Cho, I.: Direct producted W *-probability spaces and corresponding free stochastic integration. Bull. Korean Math. Soc. 44(1), 131–150 (2007)
Cho, I.: Vertex-compressed algebras of a graph von Neumann algebra. Submitted to ACTA. Appl. Math. (2007)
Cho, I.: Graph von Neumann algebras. ACTA. Appl. Math. 95, 95–135 (2007)
Cho, I.: Labeling operators of graph groupoids. Preprint (2008)
Cho, I.: Group-freeness and certain amalgamated freeness. J. Korean Math. Soc. 45(3), 597–609 (2008)
Cho, I., Jorgensen, P.E.T.: C *-subalgebras generated by partial isometries in B(H). Submitted to JMP (2007)
Cho, I., Jorgensen, P.: C *-algebras generated by partial isometries. To appear in JAMC (2008)
Dicks, W., Ventura, E.: The Group Fixed by a Family of Injective Endomorphisms of a Free Group. Contemp. Math., vol. 195. AMS, Providence
Dutkay, D.E., Jorgensen, P.E.T.: Iterated function systems, Ruelle operators and invariant projective measures. Preprint arXiv:math.DS/0501077/v3 (2005)
Exel, R.: A new look at the crossed-product of a C *-algebra by a semigroup of endomorphisms. Preprint (2005)
Fannes, M., Nachtergaele, B., Werner, R.F.: Finitely correlated states on quantum spin chains. Commun. Math. Phys. 144(3), 443–490 (1992)
Fannes, M., Nachtergaele, B., Werner, R.F.: Entropy estimates for finitely correlated states. Ann. Inst. H. Poincare Phys. Theor. 57(3), 259–277 (1992)
Fannes, M., Nachtergaele, B., Werner, R.F.: Ground states of VSB-models on Cayley trees. J. Stat. Phys. 66, 939–973 (1992)
Fannes, M., Nachtergaele, B., Werner, R.F.: Finitely correlated Pure states. J. Funct. Anal. 120(2), 511–534 (1994)
Gibbons, A., Novak, L.: Hybrid Graph Theory and Network Analysis. Cambridge Univ. Press, Cambridge (1999). ISBN:0-521-46117-0
Gill, A.: Introduction to the Theory of Finite-State Machines. McGraw-Hill, New York (1962). MR0209083 (34\#8891)
Gliman, R., Shpilrain, V., Myasnikov, A.G. (eds.): Computational and Statistical Group Theory. Contemporary Math., vol. 298. AMS, Providence (2001)
Guido, D., Isola, T., Lapidus, M.L.: A trace on fractal graphs and the ihara zeta function. Preprint arXiv:math.OA/0608060v1 (2006)
Hopcroft, J.E., Ullman, J.D.: Introduction to Automata Theory, Language, and Computation. Addision-Wesley, Reading (1979). ISBN:0-201-02988-X
Jorgensen, P.E.T.: Use of operator algebras in the analysis of measures from wavelets and iterated function systems. Preprint (2005)
Jorgensen, P.E.T., Song, M.: Entropy encoding, Hilbert spaces, and Kahunen-Loeve transforms. J. Math. Phys. 48(10) (2007)
Jorgensen, P.E.T., Schmitt, L.M., Werner, R.F.: q-Canonical commutation relations and stability of the Cuntz algebra. Pac. J. Math. 165(1), 131–151 (1994)
Kadison, R.V., Ringrose, J.R.: Fundamentals of the Theory of Operator Algebra. Grad. Stud. Math., vol. 15. AMS, Providence (1997)
Kigami, J., Strichartz, R.S., Walker, K.C.: Constructing a Laplacian on the diamond fractal. Exp. Math. 10(3), 437–448 (2001)
Kribs, D.W.: Quantum Causal histories and the directed graph operator framework. Preprint arXiv:math.OA/0501087v1 (2005)
Kribs, D.W., Jury, M.T.: Ideal structure in free semigroupoid algebras from directed graphs. Preprint
Kucherenko, I.V.: On the structurization of a class of reversible cellular automata. Diskrete Math. 19(3), 102–121 (2007)
Lind, D.A.: Entropies of automorphisms of a topological Markov shift. Proc. AMS 99(3), 589–595 (1987)
Lind, D.A., Marcus, B.: An Introduction to Symbolic Dynamics and Coding. Cambridge Univ. Press, Cambridge (1995)
Lind, D.A., Schmidt, K.: Symbolic and algebraic dynamical systems. In: Handbook of Dynamical System, vol. 1A, pp. 765–812. Elsevier, Amsterdam (2002)
Lind, D.A., Tuncel, S.: A spanning tree invariant for Markov shifts. IMA Vol. Math. Appl. 123, 487–497 (2001)
Marshall, C.W.: Applied Graph Theory. Wiley, New York (1971). ISBN:0-471-57300-0
Mitchener, P.D.: C *-categories, groupoid actions, equivalent KK-theory, and the Baum-Connes conjecture. Preprint arXiv:math.KT/0204291v1 (2005)
Myasnikov, A.G., Shapilrain, V. (eds.): Group Theory, Statistics and Cryptography. Contemporary Math., vol. 360. AMS, Providence (2003)
Potgieter, P.: Nonstandard analysis, fractal properties and Brownian motion. Preprint arXiv:math.FA/0701649v1 (2007)
Powers, R.T.: Heisenberg model and a random walk on the permutation group. Lett. Math. Phys. 1(2), 125–130 (1975)
Powers, R.T.: Resistance inequalities for KMS-states of the isotropic Heisenberg model. Commun. Math. Phys. 51(2), 151–156 (1976)
Powers, R.T.: Registance inequalities for the isotropic Heisenberg ferromagnet. J. Math. Phys. 17(10), 1910–1918 (1976)
Radulescu, F.: Random matrices, amalgamated free products and subfactors of the von Neumann algebra of a free group, of noninteger index. Invent. Math. 115, 347–389 (1994)
Raeburn, I.: Graph Algebras. CBMS, vol. 3. AMS, Providence (2005)
Renault, J.: A Groupoid Approach to C *-algebras. In: Lect. Notes in Math., vol. 793. Springer, Berlin (1980). ISBN:3-540-09977-8
Sakai, S.: C *-Algebras and W *-Algebras. Springer, Berlin (1971). MR number: MR0442701
Scapellato, R., Lauri, J.: Topics in Graph Automorphisms and Reconstruction. Lond. Math. Soc., Student Text, vol. 54. Cambridge Univ. Press, Cambridge (2003)
Schiff, J.L.: Cellular Automata, Discrete View of the World. Wiley-Interscience Series in Disc. Math. & Optimization. Wiley, New York (2008). ISBN:978-0-470-16879-0
Shirai, T.: The spectrum of infinite regular line graphs. Trans. AMS 352(1), 115–132 (2000)
Solel, B.: You can see the arrows in a Quiver operator algebras. Preprint (2000)
Speicher, R. (eds.): Combinatorial theory of the free product with amalgamation and operator-valued free probability theory. AMS Mem. 132(627) (1998)
Thompson, S., Cho, I.: Powers of mutinomials in commutative algebras. (Undergraduate Research) Submitted to PMEJ (2008)
Thompson, S., Mendoza, C.M., Kwiatkowski, A.J., Cho, I.: Lattice paths satisfying the axis property. (Undergraduate Research) Preprint (2008)
Vega, V.: Finite directed graphs and W *-correspondences. Ph.D. thesis, Univ. of Iowa (2007)
Voiculescu, D.: Symmetries of some reduced free product C *-algebras. In: Lect. Notes in Math., vol. 1132, pp. 556–588. Springer, Berlin (1985)
Voiculescu, D., Dykemma, K., Nica, A.: Free Random Variables. CRM Monograph Series, vol 1 (1992)
Weintraub, S.H.: Representation Theory of Finite Groups: Algebra and Arithmetic. Grad. Studies in Math, vol. 59. AMS, Providence (2003)
Wigner, E.P.: Characteristic vectors of bordered matrices with infinite dimensions. Ann. Math. 62(2), 548–564 (1955)
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Cho, I., Jorgensen, P.E.T. Applications of Automata and Graphs: Labeling-Operators in Hilbert Space I. Acta Appl Math 107, 237–291 (2009). https://doi.org/10.1007/s10440-008-9380-6
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10440-008-9380-6
Keywords
- Locally finite connected countable directed graphs
- Canonical weighted graphs
- Weighting processes
- Graph groupoids
- Labeled graph groupoids
- Automata
- Graph-groupoid-automata
- Automata-trees
- Fractaloids
- Right graph von Neumann algebras
- Right graph W *-probability spaces
- Labeling operators