Networks  

In General > s.a. Cellular Automaton; complexity; graph.
* Idea: Networks are finite non-empty set of objects called vertices, and a finite set of edges associated each with an unordered pair of vertices (its endpoints); A generalization of the concept of graph (they can have multiple edges).
* Embedded in a manifold: A system of segments or edges which intersect only at their endpoints, called vertices; For example, the edges of a tessellation, which are also an embedded graph.
* Applications: Cells, networks of chemicals linked by chemical reactions, the Internet or computer networks.
@ General references: Buchanan 02 [I]; Barabási; Newman PT(08)nov.
@ Complex networks: Albert & Barabási RMP(02)cm/01 [statistical mechanics]; Evans CP(04) [rev]; Boccaletti et al PRP(06) [dynamics]; Bogacz et al PhyA(06) [homogeneous, Monte Carlo]; Costa & Silva JSP(06) [hierarchical model]; West et al PRP(08) [new concepts, information exchange]; Radicchi et al PRL(08) [renormalization]; Horak et al JSM(09)-a0811-in [persistent homology].
@ Quantum localization models: Torma et al qp/01; Cardy CMP(05).
@ Quantum, other: Finkelstein et al qp/96 [of quantum points, and standard model]; Törmä PRL(98)qp [transitions]; Somma et al PRA(02) [simulating physical phenomena]; Altman et al IJTP(04)qb.NC/03 = IJTP(04) [superpositional]; Chiribella et al a0904 [theoretical framework]; Novotny et al JPA(09) [random unitary dynamics].

And Dynamical Systems > s.a. graphs in physics.
@ Evolving: Krapivsky & Derrida PhyA(04) [growing, properties]; Minnhagen et al PhyA(04) [merging and creation]; Grönlund et al PS(05) [correlations and preferential growth]; Shi et al mp/05; Shi et al PhyA(07) [clustering coefficients]; Gu & Sun PLA(08) [with node addition and deletion]; Hou et al a0808 [degree-distribution stability of growing networks], a0901 [stable degree distribution].
@ Transport, flows on networks: Jordan et al JMP(04) [fluctuations]; Stinchcombe PhyA(05) [regular and disordered networks].
@ Critical phenomena: Goltsev et al PRE(03)cm/02 [phenomenological theory]; Giuraniuc PRL(05) + pn(05)aug [interactions vs network structure]; Dorogovtsev et al RMP(08)-a0705; > s.a. renormalization, {scale-free below}.
@ Random: Dorogovtsev & Samukhin PRE(03)cm/02 [fluctuations], et al NPB(03)cm/02 [statistical mechanics], cm/02, cm/02 [construction], cm/02-in [overview], NPB(03)cm/02 [path lengths]; Derényi et al PhyA(04) [topological phase transition]; Li et al PhyA(04) [transition to chaos]; Resendis-Antonio & Collado-Vides PhyA(04) [growth as diffusion]; Luque & Ballesteros PhyA(04) [random walk networks]; Kramer et al PRP(05) [and 2D quantum phase transitions]; Franceschetti & Meester 07 [r JSP(09)]; Nowotny & Requardt JCA(07)cm/06 [emergent properties]; Ben-Naim & Krapivsky JPA(07) [addition-deletion]; Novotny et al a0904 [random unitary quantum dynamics]; > s.a. non-extensive statistical mechanics [entropy]; random tilings.
@ Related topics: Balachandran & Ercolessi IJMPA(92) [single-particle statistics]; Golubitsky & Stewart BAMS(06) [grupoid formalism]; La Mura & Swiatczak qp/07 [Markovian Entanglement Networks]; Passerini & Severini a0812 [entropy]; > s.a. entanglement, spin models.

Neural Network
* Applications: Classification of galaxies and other astronomical objects (> see astronomy).
@ References: Amit 89; Beale & Jackson 90; Biehl & Schwarze JPA(93); Dotsenko 95; Altaisky qp/01 [quantum].

Scale-Free Networks
* Idea: The network continually grows by the addition of new nodes; A new node connects to two existing nodes in the network at time t + 1; This new node is much more likely to connect to highly connected nodes (preferential attachment); The function P(k) does not have a peak and decays as a power law at large k, so most nodes have one or two links, but a few nodes (hubs) have a large number of links, which guarantees that the system is fully connected.
$ Def: A network in which the probability that any given vertex is of degree k is Prob[d(v) = k] = kgamma, where often [1,3].
@ References: Dorogovtsev et al PRE(02) [properties]; Barabási & Bonabeau SA(03)may; Dangalchev PhyA(04) [stochastic models]; Chen & Shi PhyA(04) [modeling]; Shiner & Davison CSF(04) [connectivity]; Rodgers et al JPA(05) [eigenvalue spectrum of adjacency matrix].

Other Concepts and Types > s.a. cell complex; graph types; technology [internet]; tiling.
* Network connectivity: Can be characterized by the probability P(k) that a node has k links.
* Random: (Erdös-Renyi) Each pair of nodes is connected with probability p; The function P(k) is highly peaked at some k, and decays exponentially at large k, so most nodes have approximately the same number of links; (Uniform random graph) Pick one uniformly at random.
* May-Wigner stability theorem: Increasing the complexity of a network inevitably leads to its destabilization, such that a small perturbation will be able to disrupt the entire system.
@ Random cellular networks: Vincze et al JGP(04) [Aboav-Weaire law].
@ Small-world networks: Watts 99 [r PT(00)nov]; Araújo et al PLA(03); Sinha PhyA(05) [complexity vs stability]; Cont & Tanimura AAP(08).
@ Related topics: Kim PRL(04)cm [coarse-graining]; Gelenbe PRS(08) [intro to stochastic networks].


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