Analytical Derivation of Power Laws in Firm Size Variables from Gibrat%26apos;s Law and Quasi-inversion Symmetry: A Geomorphological Approach

作者:Ishikawa Atushi*; Fujimoto Shouji; Mizuno Takayuki; Watanabe Tsutomu
来源:Journal of the Physical Society of Japan, 2014, 83(3): 034802.
DOI:10.7566/JPSJ.83.034802

摘要

We start from Gibrat%26apos;s law and quasi-inversion symmetry for three firm size variables (i.e., tangible fixed assets K, number of employees L, and sales Y) and derive a partial differential equation to be satisfied by the joint probability density function of K and L. We then transform K and L, which are correlated, into two independent variables by applying surface openness used in geomorphology and provide an analytical solution to the partial differential equation. Using worldwide data on the firm size variables for companies, we confirm that the estimates on the power-law exponents of K, L, and Y satisfy a relationship implied by the theory.

  • 出版日期2014-3