relation: http://eprints.imtlucca.it/634/
title: Scale-free models for the structure of business firm networks
creator: Kitsak, Maksim
creator: Riccaboni, Massimo
creator: Havlin, Shlomo
creator: Pammolli, Fabio
creator: Stanley, H. Eugene
subject: HB Economic Theory
subject: QC Physics
description: We study firm collaborations in the life sciences and the information and communication technology sectors. We propose an approach to characterize industrial leadership using k-shell decomposition, with top-ranking firms in terms of market value in higher k-shell layers. We find that the life sciences industry network consists of three distinct components: a “nucleus,” which is a small well-connected subgraph, “tendrils,” which are small subgraphs consisting of small degree nodes connected exclusively to the nucleus, and a “bulk body,” which consists of the majority of nodes. Industrial leaders, i.e., the largest companies in terms of market value, are in the highest k-shells of both networks. The nucleus of the life sciences sector is very stable: once a firm enters the nucleus, it is likely to stay there for a long time. At the same time we do not observe the above three components in the information and communication technology sector. We also conduct a systematic study of these three components in random scale-free networks. Our results suggest that the sizes of the nucleus and the tendrils in scale-free networks decrease as the exponent of the power-law degree distribution λ increases, and disappear for λ≥3. We compare the k-shell structure of random scale-free model networks with two real-world business firm networks in the life sciences and in the information and communication technology sectors. We argue that the observed behavior of the k-shell structure in the two industries is consistent with the coexistence of both preferential and random agreements in the evolution of industrial networks.
publisher: American Physical Society
date: 2010-03
type: Article
type: PeerReviewed
format: application/pdf
language: en
identifier: http://eprints.imtlucca.it/634/1/PhysRevE.Pammolli_Riccaboni_2010.pdf
identifier:   Kitsak, Maksim and Riccaboni, Massimo and Havlin, Shlomo and Pammolli, Fabio and Stanley, H. Eugene  Scale-free models for the structure of business firm networks.  Physical Review E, 81 (3).  036117.  ISSN 1539-3755      (2010)  
relation: http://link.aps.org/doi/10.1103/PhysRevE.81.036117
relation: 10.1103/PhysRevE.81.036117