Indirect substitution may be modelled as a form of “allocation based on some other relationship” when a co-product is assumed to displace a marginal or average market-equivalent product via market-mediated processes.
Indirekte substitution kan beskrives som en form for "fordeling baseret på et andet forhold", når et sideprodukt antages at fortrænge et marginalt eller ækvivalent gennemsnitprodukt via markedsprocesser.