AMMと流動性プール
Uniswapなどの自動マーケットメーカー（AMM）の仕組みと、流動性プールが分散型取引を可能にする方法を理解します。
「AMMと流動性プール」はCoddyKit上の無料Blockchain Smart Contracts with Solidityレッスンです。 これはレッスン1/4です。 下記で完全なレッスンを無料で読むことができます。その後、ブラウザ内の組み込みコードエディタと24時間対応のAIチューターでハンズオン演習できます。 これはBlockchain Smart Contracts with Solidity学習パスの一部であり、ウェブとCoddyKitアプリ全体で進捗が同期されます。 Blockchain Smart Contracts with Solidityコースには全4レッスンが含まれています。
このレッスンの一部はまだ翻訳されておらず、英語で表示されています。
Welcome to AMMs
Decentralized Finance (DeFi) has revolutionized how we trade assets. At its heart are Automated Market Makers (AMMs).
AMMs power decentralized exchanges (DEXs) like Uniswap, allowing users to swap tokens without traditional buyers and sellers.
Instead of matching orders, AMMs use mathematical formulas and liquidity pools.
Order Books vs. AMMs
Traditional exchanges use order books, where buyers and sellers list their desired prices. Trades only happen when bids and asks match.
- Order Books: Centralized, requires matching orders, can suffer from low liquidity.
- AMMs: Decentralized, uses liquidity pools, always offers a price determined by a formula.
AMMs solve the liquidity problem for many token pairs on a blockchain by always providing a market.
The Power of Liquidity Pools
An AMM's backbone is the liquidity pool. This is a collection of two or more tokens locked in a smart contract.
For example, a common pool might hold ETH and a stablecoin like DAI. Users can swap between these tokens directly from the pool.
These pools are funded by individuals called Liquidity Providers (LPs).
Meet the Constant Product Formula
Most AMMs, like Uniswap, use the constant product formula: x * y = k.
xis the quantity of the first token.yis the quantity of the second token.kis a constant product that must remain unchanged after a trade.
When you swap tokens, the quantities of x and y change, but their product k stays the same, determining the new price ratio.
How to Become an LP
Liquidity Providers (LPs) deposit an equal value of two tokens into a liquidity pool. For example, $1000 worth of ETH and $1000 worth of DAI.
In return, LPs receive Liquidity Pool (LP) tokens. These tokens represent their share of the pool.
LP tokens can be redeemed later to withdraw your original deposit plus any accumulated fees.
Adding Liquidity in Practice
When an LP adds liquidity, they increase the total supply of x and y in the pool, which also increases the constant k.
The AMM smart contract ensures that tokens are added in the correct ratio to maintain the pool's balance and prevent immediate price changes.
This process makes the pool deeper, allowing for larger trades with less price impact.
Swapping Tokens
When a user wants to swap Token A for Token B, they send Token A to the liquidity pool.
The AMM's smart contract then calculates how much Token B to give back, based on the x * y = k formula.
The pool's balance shifts, and the price of the tokens adjusts automatically according to the formula.
Code Example: Simulating a Swap
Let's see a simplified Solidity contract that simulates how an AMM might perform a swap using the constant product formula.
This example demonstrates the core calculation and reserve update.
pragma solidity ^0.8.0;
contract SimpleAmmSwap {
uint public tokenXReserve = 1000 * 10**18; // 1000 tokens (e.g., ETH) with 18 decimals
uint public tokenYReserve = 1000 * 10**18; // 1000 tokens (e.g., DAI) with 18 decimals
uint public k = tokenXReserve * tokenYReserve;
// Simulate a swap from Token X to Token Y
// For simplicity, no actual token transfers, just reserve updates.
function swapXForY(uint amountInX) public returns (uint amountOutY) {
require(amountInX > 0, "Amount in must be positive");
// Calculate new reserves and output amount
uint newXReserve = tokenXReserve + amountInX;
uint newYReserve = k / newXReserve;
amountOutY = tokenYReserve - newYReserve;
require(amountOutY > 0, "Not enough liquidity for swap");
// Update reserves
tokenXReserve = newXReserve;
tokenYReserve = newYReserve;
// Note: In a real AMM, actual token transfers would occur here.
}
// A getter to check current reserves
function getReserves() public view returns (uint, uint) {
return (tokenXReserve, tokenYReserve);
}
}Understanding Impermanent Loss
One major risk for LPs is impermanent loss. This occurs when the price of the assets in the liquidity pool changes relative to when you deposited them.
If the price ratio diverges significantly, the value of your tokens withdrawn from the pool might be less than if you had simply held them outside the pool.
It's called "impermanent" because the loss only becomes permanent if you withdraw your liquidity before the prices return to their original ratio.
LP Fees and Rewards
Despite impermanent loss, LPs are incentivized by earning a share of the trading fees generated by the pool.
Each time a trade occurs, a small percentage (e.g., 0.3%) of the swapped amount is added to the liquidity pool.
These fees accumulate in the pool and are distributed proportionally to LPs when they withdraw their liquidity, compensating them for providing capital and taking on impermanent loss risk.
Quick Check: AMM Basics
Test your understanding of Automated Market Makers and Liquidity Pools.
Recap: AMMs & Liquidity Pools
We've explored how Automated Market Makers (AMMs) provide decentralized trading by using liquidity pools instead of traditional order books.
Key takeaways:
- AMMs use formulas like
x * y = kto determine prices. - Liquidity Providers (LPs) fund pools and earn trading fees.
- Impermanent loss is a risk for LPs due to price divergence.
Understanding these concepts is vital for navigating the DeFi landscape!
よくある質問
「AMMと流動性プール」レッスンは無料ですか？
はい。「AMMと流動性プール」の完全なテキストはこのウェブで無料で読めます。インタラクティブに演習し（組み込みコードエディタと24時間対応のAIチューター）、Blockchain Smart Contracts with Solidityコースの残りをアンロックするには、CoddyKit PROにアップグレードしてください。 Blockchain Smart Contracts with Solidityコースには全4レッスンが含まれています。
「AMMと流動性プール」で何を学びますか？
Uniswapなどの自動マーケットメーカー（AMM）の仕組みと、流動性プールが分散型取引を可能にする方法を理解します。 ブラウザで直接実行するハンズオンコードでBlockchain Smart Contracts with Solidityを演習し、24時間対応のAIチューターがレッスンを進める中での質問に答えます。
Blockchain Smart Contracts with Solidityを始めるのに経験は必要ですか？
事前経験は必要ありません。CoddyKitのBlockchain Smart Contracts with Solidityは初級者から上級者向けに構成されているため、ここから始めるか最初から始めて、自分のペースで進むことができます。 これはレッスン1/4です。
「AMMと流動性プール」レッスンにはどのくらい時間がかかりますか？
ほとんどのCoddyKitレッスンは約5～10分かかります。各レッスンはコンパクトでインタラクティブなので、着実に進歩し、ウェブとアプリ全体で正確に前回の場所から再開できます。
このBlockchain Smart Contracts with Solidityレッスンでコードを書いて実行できますか？
はい。すべてのBlockchain Smart Contracts with Solidityレッスンに組み込みコードエディタが含まれているため、ブラウザでリアルコードを書いて実行し、即座のAIフィードバックを取得できます。ローカル設定は不要です。