INDEXATION in economics: the action of readjusting a security or debt according to officially determined inflation so that the debt continues to represent the same real value over time. There are two traditional methods of INDEXATION: the first is for the central bank, ministry of finance, economy or relevant institution to officially announce the amount of inflation (positive or negative) per month and apply this percentage to the total outstanding debt; the second is that the debt is fixed in units of a fictitious but legal currency, calculated by the competent authority (UF, or development units in Chile), variable according to inflation. The number of UFs remains unchanged with respect to indexation but this unit is readjusted month by month according to official inflation. For example, if a debt of 100 UF is acquired payable in 10 installments, each installment will always be 10 UF, but the UF will increase monthly in value according to the monthly inflation (in most countries called CPI, by consumer price index) and thus will increase (or decrease if there is negative inflation) month by month the value in local currency to be canceled. 2 . Sort a list according to an index (alphabetical, ascending numeral, descending, or otherwise)