マーク・メザールとブショーの貧富の格差の原因を説明した論文

マーク・メザール氏のサイトの発表論文一覧で、彼が発表した論文が読めます。貧富の差が生まれる理由、つまり資産の分布がべき乗則に従う理由を明らかにした次の論文も、pdfファイルで読めてしまいます。私は数学が分からないのでさっぱりですが。

"Wealth condensation in a simple model of economy", J.-P. Bouchaud and M. Mezard, Physica A 282 536 (2000).

Abstract

We introduce a simple model of economy, where the time evolution is described by an
equation capturing both exchange between individuals and random speculative trading,
in such a way that the fundamental symmetry of the economy under an arbitrary change
of monetary units is insured. We investigate a mean-field limit of this equation and
show that the distribution of wealth is of the Pareto (power-law) type. The Pareto
behaviour of the tails of this distribution appears to be robust for finite range models,
as shown using both a mapping to the random ‘directed polymer’ problem, as well as
numerical simulations. In this context, a transition between an economy dominated
by a few individuals from a situation where the wealth is more evenly spread out,
is found. An interesting outcome is that the distribution of wealth tends to be very
broadly distributed when exchanges are limited, either in amplitude or topologically.
Favoring exchanges (and, less surprisingly, increasing taxes) seems to be an efficient
way to reduce inequalities.