Definition
VOA + PTAX = VOM
See overview of GTAP framework
VOA: Value of output at agent's price
PTAX: Producer tax / subsidy
VOM: Value of output at market price
Note: Recall that PA = PM * T
VOM(i) = VPM(i) + ΣVFM(i,j) + VGM(i)
VPM: Value of sales to private household at market price
VFM: Value of sales to firms at market price (use of goods i in production of goods j)
VGM: Value of sales to government at market price