In the ERC model, each player$$s utility function Ui depends on their own monetary payoff xi and the distribution of payoffs. The utility function is:

Ui$=$xi$$i$($xixi$+$xj$1$n$)2$

where:

xi is the monetary payoff of Player i

xj is the monetary payoff of the other player $($j$)$

i is Player i$\text{'}$s inequality aversion parameter

n represents the number of participants in the game $(2$ in all cases below$)$

This function implies that Player i$\text{'}$s utility decreases as the inequality between their payoff and the other player$$s payoff increases, weighted by their inequality aversion parameter i$.$