  Given the wealth inequality worldwide, there is an urgent need to identify
the mode of wealth exchange through which it arises. To address the research
gap regarding models that combine equivalent exchange and redistribution, this
study compares an equivalent market exchange with redistribution based on power
centers and a nonequivalent exchange with mutual aid using the Polanyi,
Graeber, and Karatani modes of exchange. Two new exchange models based on
multi-agent interactions are reconstructed following an econophysics approach
for evaluating the Gini index (inequality) and total exchange (economic flow).
Exchange simulations indicate that the evaluation parameter of the total
exchange divided by the Gini index can be expressed by the same saturated
curvilinear approximate equation using the wealth transfer rate and time period
of redistribution and the surplus contribution rate of the wealthy and the
saving rate. However, considering the coercion of taxes and its associated
costs and independence based on the morality of mutual aid, a nonequivalent
exchange without return obligation is preferred. This is oriented toward
Graeber's baseline communism and Karatani's mode of exchange D, with
implications for alternatives to the capitalist economy.
