CollateralAuctionHouse is used to sell collateral from SAFEs that have become under-collateralized in order to preserve the overall health of the system. There are two flavours of collateral auctions: English and FixedDiscount. English auction version requires that bidders compete with increasing amounts of system coins for a fixed amount of collateral and only one bidder can win. This auction type has two phases: increaseBidSize where bidders submit higher system coin bids and decreaseSoldAmount where bidders accept a lower collateral amount for the winning system coin bid.FixedDiscount and IncreasingDiscount auctions only have one phase (buyCollateral) where bidders submit system coins and the smart contract offers them collateral at a discounted price compared to its market price. These auction types are more capital efficient and user friendly compared to English auctions. They also allow anyone to buy collateral using flashloans.OSM price (which will lag compared to the actual collateral market price) and the system coin's redemptionPrice in order to calculate the amount of collateral to offer in exchange for each individual bid. There is the possibility for governance to set the contract's parameters so that it uses the collateral's medianizer price and/or the system coin's market price if they deviated within certain limits from the FSM price and the redemptionPrice.DebtAuctionHouse is used to get rid of the AccountingEngine’s debt by auctioning off protocol tokens for a fixed amount of surplus (system coins). After the auction is settled, it sends the received surplus to the AccountingEngine in order to cancel out bad debt and it also mints protocol tokens for the winning bidder.SurplusAuctionHouse (all of its Burning, Recycling and PostSettlement versions) is used to get rid of the AccountingEngine’s surplus by auctioning off a fixed amount of internal system coins in exchange for protocol tokens. After auction settlement, the auction house either burns the winning protocol token bid or it transfers the bid to an external address and then sends internal system coins to the winning bidder.English, Debt and Surplus auctions there are three main parameters:bidIncrease- if it's too high it will discourage bidding and if it's too low its effect will be insignificantbidDuration- if it's too high it would force the winning bidder to wait too long until they can collect their winnings. If it's too low it would not give other bidders enough time to participatetotalAuctionLength- if it's too high it would only delay auction settlement without any positive impact on the outcome. If it's too low it would make the auction settle before the true price is found.bidToMarketPriceRatio (only in English collateral auctions) - minimum mandatory size of the first bid compared to collateral price coming from the OSMFixedDiscount collateral auctions there's a wider range of variables:totalAuctionLength- same parameter as in the other auction typesdiscount- discount applied to the collateral priceminimumBid- minimum system coin bid that must be submitted by any bidderupperCollateralMedianDeviation- maximum upper side medianizer price deviation (compared to the OSM price) used by the auction contract to determine whether it will use the median or the OSM as a feed sourcelowerCollateralMedianDeviation- maximum lower side medianizer price deviation (compared to the OSM price) used by the auction contract to determine whether it will use the median or the OSM as a feed sourcelowerSystemCoinMedianDeviation - maximum lower side system coin market price (compared to the redemption price) used by the auction contract to determine whether it will use the market or the redemption price when determining the amount of collateral boughtupperSystemCoinMedianDeviation - maximum upper side system coin market price (compared to the redemption price) used by the auction contract to determine whether it will use the market or the redemption price when determining the amount of collateral bought minSystemCoinMedianDeviation - minimum deviation between the market and the redemption prices of the system coin in order for the contract to choose the market price (and not the redemption one) when it determines the amount of collateral boughtIncreasingDiscount collateral auctions, the parameter range is almost identical to the one in FixedDiscount auctions, with some additions:minDiscount - minimum discount (compared to the system coin's current redemption price) at which collateral is being soldmaxDiscount - maximum discount (compared to the system coin's current redemption price) at which collateral is being soldperSecondDiscountUpdateRate - rate at which the discount will be updated in an auctionmaxDiscountUpdateRateTimeline - max time over which the discount can be updated in an auction