版权声明（Copyright Notice）
本文翻译自@SwivelFinance的文章：A Basic Description and Visualization of the Swivel Protocol’s mechanics。已得到作者的授权。译者为@chainguys。转载请注明作者和译者。
（Coptyright©2021 by @SwivelFinance, translated by @chainguys）
本翻译文章所展示的一切信息都只是为了学习和交流目的，不能也不应成为任何财务或投资建议。
(All content shown are for communication and learning purposes, cannot and should not be viewed as any form of Financial or Investment Advice)
1. 导言（Introduction）
Concerns surrounding protocols like Compound and Aave have become acceptable for all but the most risk-averse market participants. However, the volatility of DeFi rates still precludes many from effective portfolio/risk management, and others from market participation entirely.
尽管（之前）对Compound和AAVE有所担忧，但大多数人现在认为它们是可以接受的了 — — 除了大多数风险厌恶的市场参与者。但是，DeFi市场的波动性依然使得一部分人无法进行有效的风险管理，让其他人无法完全参与市场。
Swivel enables this wider market participation by providing the capital efficient infrastructure and professional trading interface necessary for tokenized cash-flows.
Swivel通过对代币化现金流（tokenized cash-flows）提供资本高效(capital efficient)的基础设施和专业的交易界面来实现更广泛的市场参与。
1.1 代币现金流（Tokenizing Cash-Flows）
At it’s core, Swivel is built around the concept of cash flow-tokenization.
Specifically, Swivel provides the ability to split a single interest generating token into two separate cash-flow tokens until a future date. One cash-flow being the interest generated, and the other being ownership of the underlying token, redeemable at that future date.
In Swivel’s design these two are referred to as nTokens (yield-generating tokens), and zcTokens (tokens redeemable at maturity).
Swivel以“将现金流代币化”为核心创立。
详细来说，Swivel提供这样一种能力：（用户）可以将一个利率生成代币一分为二，生成两个绑定日期的现金流代币。其中一个现金流代币（表示）利率生成，另一个则代表所有权，并且在到期后可以赎回。在Swivel的系统中，第一个叫做nTokens，第二个叫zcTokens。
（@chainguys省流助手：就是利率和本金分别开来，各用各的token来表示）
将USDC分别铸造成nTokens和zcTokens
2. zcTokens
2.1 概览（Overview）
ERC-20 Tokens that represent a 1–1 claim for underlying upon maturity.
一个可以在到期日1比1赎回标的资产（本金）的ERC-20代币
Zero-coupon tokens, zcTokens, are ERC-20’s which are redeemable 1:1 at maturity for an underlying token.
零息代币，即**zcTokens** 是一个可以在到期日1比1赎回标的资产（本金）的ERC-20代币
As users lock-in fixed yields, their deposit is split into zcTokens and nTokens and the the nTokens minted are sold to fuel a fixed-yield.
用户锁定固定收益时，他们的入金会被分为zcTokens 和 nTokens。nTokens会被卖出作为一个固定收益的燃料（to fuel a fixed-yield）。
This leaves the lender with an immediate fixed-yield and their minted zcTokens.
这使得贷款人能够马上获得一个固定收入和一个zcTokens
Fixed-Yield Lending:
Alice has 1000 USDC.
Alice fills Bob’s order, splitting 1000 USDC into 1000 zcUSDC and 1000 nUSDC.
Alice sells 1000 nUSDC to Bob for 50 USDC.
Alice then has 1000 zcUSDC. At maturity Alice redeems her 1000zcUSDC for 1000 USDC. This leaves Alice with 1050 USDC.
整个过程如下：
Alice有1000USDC
Alice相应Bob的订单，将1000USDC分成了1000zcUSDC和 1000nUSDC
Alice将1000 nUSDC以50USDC的价格卖给Bob
Alice现在就有1000zcUSDC,在到期后Alice将1000zcUSDC赎回，拿回1000USDC
这样Alice就有1050USDC
以5%年利率出借
2.2 定价（Pricing）
Given zcTokens represent a 1–1 redemption only upon maturity, they are discounted at a rate based on the predicted amount of interest that may have otherwise been generated until the maturity/redemption date (the nToken price).
Accepting that this potential yield decreases as time passes, ZcTokens appreciate towards par and reach par as maturity is reached.
Further, because an nToken represents the predicted future yield, the discount on a zcToken is inversely proportional to the cost of an nToken.
At maturity, zcTokens begin to appreciate above par, accruing the yield generated on a given money-market (e.g. Compound) until redeemed.
假设zcTokens在到期日能够按1：1赎回，那么它们就可以（跟传统债券一样）来根据变现日期和利率情况来定价。
随着时间流逝，可能的收益就会减少，zcTokens也会越来越接近标的资产价格。
接着，因为nToken代表了预计的未来收益，zcToken的折扣价格将会和nToken的价值成反比。
到期时，zcTokens价格开始超过面值，在正式赎回之前会以某个流动性市场（如compound）上的情况来累积收益。
2.3 退出/卖出zcTokens Exiting/Selling zcTokens
An example of common market interactions
一个普通市场交互的案例
As rates fluctuate, active market participants may require the ability to fluidly move in and out of positions.
To facilitate this market participation, Swivel provides the ability to frictionlessly exit or sell a zcToken position.
由于（利率）会波动，主动的市场参与者会要求有迅速调整仓位的能力。为了帮助这样的市场参与行为，Swivel会提供这样无摩擦地退出或卖出zcToken仓位的能力。
Exiting zcTokens early by purchasing nTokens and then redeeming for underlying:
Alice has 1000 zcUSDC.
Alice fills Bob’s order, purchasing 1000 nTokens.
Alice redeems 1000 zcUSDC and 1000 nUSDC for 1000 USDC and then pays Bob 50 USDC.
This leaves Alice with 950 USDC.
提前卖出zcToken仓位的交易过程如下：
Alice有1000 zcUSDC
Alice响应Bob的订单，购买了1000 nTokens
Alice用 1000zcUSDC和 1000nUSDC赎回了1000 USDC 然后向Bob支付了50USDC
这样Alice就有950USDC了
zcTokens can also be sold to counterparties looking to take fixed-yield positions through the orderbook:
Alice has 1000 zcUSDC.
Alice fills Diane’s order, in the process Alice splitting Diane’s 1000 USDC into zcUSDC and nUSDC.
Alice purchases 1000 nUSDC from Diane and redeems her 1000 zcUSDC + 1000 nUSDC for 1000 USDC.
Alice then pays Diane a 50 USDC premium for the purchased nUSDC.
This leaves Alice with 950 USDC.
(Simplified to 1000 zcUSDC <-> 950 USDC)
zcTokens也可以被卖给寻求固定收益仓位的交易对手：
Alice有1000zcUSDC
Alice响应Diane的订单，在过程中Alice将Diane的1000USDC拆分成了zcUSDC和nUSDC
Alice从购买了1000 nUSDC, 然后将（1000 zcUSDC + 1000 nUSDC）打包赎回了1000USDC
Alice然后付给了Diane 50USDC作为费用
这样Alice就有了950USDC
将zcTokens卖给寻求固定收益仓位的交易对手
2.4 二级自动做市商（Secondary AMM’s）
A discussion of potential secondary markets and cross-chain access to fixed-yields.
一场关于潜在的二级自动做市商和跨链固定收益的讨论
zcTokens can also be traded on a secondary AMM in order to enter or exit lending positions, or alternatively attempt to amplify yield by providing liquidity.
(see: Risks of LPing in derivative marketplaces)
为了开/平仓，zcTokens也可以在二级自动做市商或者其他的流动性提供商处交易。
Entering:
Alice has 1000 USDC and wants a fixed yield.
Alice purchases 1050 zcTokens for 1000 USDC, maturing in one year for a 5% yield.
Exiting:
Alice has 1050 zcTokens and wants to exit.
Alice sells 1050 zcTokens for 1000 USDC.
进入：
Alice有1000USDC并且想获得固定收益
Alice用1000USDC购买了1050 个一年后到期且年利率5%的zcTokens
退出：
Alice有1050个zcTokens并且想退出
Alice 将1050 个zcTokens 以1000USDC卖出
3. nTokens
Notional Tokens contained in Swivel’s Vaults which represent the claim to underlying yields.
放在Swivel库房中，代表标的资产的名义代币
3.1 概览（Overview）
When a user buys nTokens, they create a vault that tracks their balances within a given market.
Each vault contains two balances, Notional and Redeemable.
当一个用户购买nTokens时，系统会（自动）在指定市场生成一个可以追踪余额的金库（valut），每个金库都有两类余额，名义的和可赎回的。
名义代币nTokens ,Notional (nTokens)
Notional Tokens (nTokens) represent a 1–1 deposit, currently generating interest in an underlying protocol. Once maturity has been reached, interest-generation ceases and nTokens become worthless.
As such, nTokens are deprecating assets that experience time-decay. As time passes, nTokens decrease in value, and as they approach maturity, an their value approaches 0.
名义代币_(nTokens)_ 达标在一个标的协议中1：1存入并生息。一旦到期，生息就停止，该代币也就失效。如此，nTokens是一个随着时间不断贬值的资产。随着时间流逝，nTokens也不断贬值，到期后归零。
可赎回（余额）Redeemable
The Redeemable represents the amount of accrued interest currently available to redeem.
As users interact with their vault, interest is accumulated to the redeemable balance, and this balance can be redeemed at any time.
可赎回（余额）代表了目前累积的且可赎回的利息。只要用户与金库交互，利息就会自动归集到可赎回的余额，并且可以立即操作赎回。
3.2 购买nTokens(Buying nTokens):
Bob has 50 USDC.
Bob fills Alice’s order selling 1000 nUSDC at .05/ea (5%), paying Alice an immediate $50 premium.
Once filled, Alice mints 1000 zcUSDC and 1000 nUSDC, transferring 1000 nUSDC to Bob. Bob then owns 1000 nUSDC (the right to the yield generated by 1000 USDC).
Bob有50USDC
Bob响应Alice的订单，卖出年利率5% 的1000 nUSDC，立刻付给Alice 50美金的费用
Alice获得1000zcUSDC和1000nUSDC后，将1000nUSDC发送给Bob
Bob现在就又1000 nUSDC(也就是获得1000USDC产生的利息)
3.3 定价（Pricing）
Given nTokens represent a 1–1 deposit into an underlying money-market, and the claim to the deposit’s future yield, they are priced based on the expected yield generated until maturity.
This potential future yield decreases as time passes and as such, nTokens depreciate and experience theta-decay.
Of note, because a zcToken represents an underlying token stripped of nToken yields, the cost of a nToken is inversely proportional to the discount on a zcToken.
假如nTokens在标定市场 1：1存入和未来对（利息）收入的权利不变，nTokens的价格就和到期日前的预期收益有关。nTokens随着时间流逝而贬值。注意，因为zcToken代表ntoken剥离的标的资产的收益，nTokens的费用和zcToken的折扣成反比。
3.4 退出/卖nTokens（Exiting/Selling nTokens）
An example of common market interactions
一个常见的市场交互案例
As with zcTokens, as rates fluctuate, active market participants require the ability to fluidly move in and out of nToken positions. To facilitate this market participation, Swivel provides the ability to exit/sell nTokens on our orderbook.
由于利率会波动，主动的市场参与者会要求有迅速调整仓位的能力。为了帮助这样的市场参与行为，Swivel会提供这样退出或卖出nTokens仓位的能力。
Selling nTokens to an initiating counterparty:
Bob has 1000 nUSDC. Bob fills Charlie’s order for 1000 nUSDC, and in return receives 50 USDC. This leaves Bob with 50 USDC + any accrued interest.
Bob有1000nUSDC.Bob响应Charlie的订单，卖出1000nUSDC,收到了50USDC。所以现在Bob在归集的利息上就多了50USDC
交易ntokens
nTokens can also be sold to counterparties redeeming their zcTokens early:
Bob has 1000 nUSDC.
Bob fills Alice’s order, selling Alice 1000 nTokens.
Alice redeems 1000 zcUSDC + 1000 nUSDC for 1000 USDC and then pays Bob 50 USDC.
This leaves Bob with 50 USDC + any accrued interest.
nTokens也可以卖给要提前用zcTokens（赎回USDC）的交易对手：
Bob有1000 nUSDC.
Bob响应Alice的订单，买了1000个nTokens给Alice.
Alice用（1000 zcUSDC + 1000 nUSDC）赎回了自己的1000USDC，然后支付给Bob 50USDC
这样Bob归集的利息上就多了50USDC
向持有zcTokens的人卖出nTokens
4. 资本效率（Capital Efficiency）
An overview of capital efficiency within Interest-Rate Derivative and Cash-Flow Markets
利率衍生品和现金流市场二者资本效率的回顾
4.1 自动做市商与订单簿（AMM vs. Orderbook）
AMM’s have insofar proven to be the effective mechanism for bootstrapping liquidity, however the efficacy and capital efficiency of AMM’s within derivative markets has proven to be questionable at best.
Without the ability to adjust quoted prices with regard to standard derivative pricing variables, liquidity providers are exposed to significant risk and constantly give up an edge to the market. (As seen in LP returns)
自动做市商目前被证明是一个提升流动性的有效机制。然而自动做市商在衍生品市场的功能和资本效率却尤其受到质疑。由于不能根据标准的衍生品价格变量来调整引用的价格，流动性提供者暴露在巨大的风险之中并且持续丧失在市场中的优势地位（请看下图LP的回报）。
Hegic LP -25%的年化收益
Swivel instead attempts to bootstrap liquidity by providing the same token incentives present on most AMM’s, but with the enhanced capital efficiency and flexibility that an orderbook can provide for all market participants.
Using Swivel’s capital efficient orderbook, not only do users receive reduced slippage and a potentially gas-free experience, but liquidity providers can account for the factors that would otherwise leave them exposed.
Swivel则尝试用与大多数自动化做市商相同，但比传统订单簿给市场参与方带来的，更有资本效率和灵活性的代币激励，来提升市场的流动性。
使用Swivel的资本有效订单簿（capital efficient orderbook），不但可以让用户减少滑点和甚至拥有无gas的交易体验，还可以让流动性提供者们发现那些可能让他们处于风险的因素。
4.2特定手段的优化（Instrument-Specific Optimizations）
If then attempting to address Swivel’s market with an AMM, one would need both a time-appreciating AMM for zero-coupon tokens (similar to Element), and a time-depreciating AMM for interest-coupons (similar to Pendle).
如果要用自动化做市商来处理Swivel这个市场，那就同时需要一个随着时间升值的零息代币自动化做市商（类似Element）和一个随着时间贬值的票息（代币）自动化做市场（类似于Pendle）。
With Swivel’s flexible orderbook, these separate AMM’s are not necessary as a user can enter the marketplace with an underlying currency (USDC, ETC, BTC, etc.,), or alternatively with either zero-coupon tokens or money-market notional (interest-coupons) when exiting positions.
As a result Swivel’s users benefit from the generalized efficiencies provided by an orderbook, and the further ~2x enhanced capital efficiency when compared to two separate AMM’s.
使用 Swivel 的灵活订单簿，这些单独的 AMM就不再是必需的了。因为用户可以使用标定的货币（USDC、ETC、BTC 等）进入市场，或者在退出时使用零息代币或货币市场名义（票息）退出头寸时。
因此 Swivel 的用户受益于订单簿提供的更广泛性效率和更多的东西 — — 与两个独立的 AMM 相比，资本效率提高了2倍。
4.3 铸造nTokens ,Minting nTokens (Interest-Coupons)
Swivel’s issuance of interest-coupons, termed Notional Tokens (nTokens), is optimized in two ways:
1.nTokens include interest-generation and tracking functionality within their transfer function which:
Reduces the deposit overhead present in designs which require increasing deposits over time
Reduces complexity in nToken pricing
Allows interest to be redeemed at any time
2.Swivel atomically mints tokens as orders are filled which reduces the number of transactions necessary for most use cases.
Swivel的发行票息，即名义代币（nTokens），主要有两个优化方向。
其一是nTokens中利息产生、追踪和转移的环节：
l 在设计中减少不断存入时会产生的损耗（费用）
l 减少nTokens定价中的问题
l 允许利息随时可赎回
其二，Swivel铸币时会尽量用最少的交易（步骤）响应最多的用户需求。
5. 流动性奖励（Liquidity Incentives）
A description of Swivel’s liquidity and market-making incentivization.
Swivel流动性和做市激励简介
Swivel is the first orderbook-based protocol with liquidity incentives built baseline into token distribution and protocol design.
In the context of an AMM, liquidity incentives are straightforward. Any user who provides pooled liquidity across the constant x*y=k curve is rewarded at a proportional rate for their liquidity provided.
Swivel是世界上第一个以订单簿为基础的，在代币分配和协议设计时就融入了流动性激励得协议。以自动化做市商的角度来说，流动性激励是直接的。任何一个基于x*y=k曲线（自动化做市基本原理）来提供流动性的人都将按比例获得激励。
When applying this concept to an orderbook, liquidity rewards are not pools but binary orders. Either an order gets filled, or it does not.
With this accepted, how does one reward those providing liquidity to an orderbook? By providing token rewards only to those liquidity providers (makers) who’s orders are filled.
Swivel sets aside 50% of our token supply for these orderbook liquidity incentives.
There are other alternative methods of weighing rewards based on orderbook state as described in Hummingbot’s paper on liquidity mining, however none serve to properly democratize access to rewards across any market participant.
当将这一概念应用到订单簿时，流动性的奖励将不再（基于）AMM池而是买卖双方的订单。一个订单要么被响应，要么不会被响应。基于此，如何奖励那些为订单簿提供流动性的人呢？答案是：只对那些订单簿被相应的流动性提供者基于代币奖励。Swivel会将50%的代币作为流动性奖励。当然，在这篇官流动性挖矿的文章中（Hummingbot’s paper）有一些其他的，基于订单簿状态来衡量奖励的方法，但所有这些都没有使得所有市场参与者更民主地参与奖励的（分配）。
5.1 流动性激励的有效性AMM vs CLOB（Effectiveness of Liquidity Incentives: AMM vs CLOB）
While liquidity provider token incentives have historically related to providing liquidity on an AMM, it appears that their positive effect on slippage/spread is enhanced within the context of an orderbook.
Effectively, within an orderbook users have individualized capital allocation, and with our liquidity rewards, more efficient competitive capital allocation results in more reward generation.
This then gives market-makers the incentive to not only optimize their capital efficiency, but in doing so undercut one another as they attempt to take on a competitive position within the orderbook.
虽然流动性提供者的代币激励与一个自动化做市商提供流动性的历史（数据）有关，不过似乎他们在订单簿条件下对解决滑点和价差起了更积极的作用。在订单簿的情况下，用户会有个性化的资产配置，那么在Swivel的流动性奖励机制下，更多有效率的竞争性资产配置将会产出更多的奖励。这将使得做市商不但会想办法最优化他们自己的资本市场效率，而且还会使他们之间互相竞价，因为他们之间处于竞争地位。
