redeem fxTokens for their face value in collateral
any fxToken can be redeemed for protocol collateral at a 1:1 ratio* this mechanism ensures that in the case an fxToken trades at a discount to its face value, an arbitrage opportunity exists, thus creating an incentive to drive it back to parity.
*only collateral from vaults that have a current c-Ratio < min c-Ratio can be redeemed against. if there are no 'underwater' vaults then users will receive a warning message "no underwater vaults available for redemption".
redeem 1 fxCNY for 1 CNY of collateral
users who redeem will receive both any arbitrage profits from discounted fxTokens and 50% of any vault liquidation fees .