Scale-free Networks from Optimal Design

TL;DR

This paper demonstrates that scale-free and small-world properties can emerge in software architecture graphs through local optimization processes, challenging the notion that such patterns only arise from specific mechanisms.

Contribution

It provides the first evidence that scale-free networks can result from a well-defined local optimization process in software architecture.

Findings

Software architecture graphs are scale-free despite tree-like design rules.

Local optimization leads to heterogeneous, scale-free network structures.

Implications for understanding the emergence of complex network patterns.

Abstract

A large number of complex networks, both natural and artificial, share the presence of highly heterogeneous, scale-free degree distributions. A few mechanisms for the emergence of such patterns have been suggested, optimization not being one of them. In this letter we present the first evidence for the emergence of scaling (and smallworldness) in software architecture graphs from a well-defined local optimization process. Although the rules that define the strategies involved in software engineering should lead to a tree-like structure, the final net is scale-free, perhaps reflecting the presence of conflicting constraints unavoidable in a multidimensional optimization process. The consequences for other complex networks are outlined.