Master Thesis Project of Matthias Nadler, University of Basel

Supervised by Prof. Dr. Fabian Schär, Credit Suisse Asset Management (Schweiz) Professor for Distributed Ledger Technologies and Fintech Center for Innovative Finance, University of Basel

Read the full thesis, including the LGT Whitepaper.

Visit lgt.exchange to start saving gas on your transactions and deployments today!

The Liquid Gas Token (LGT) combines an ERC20 Gas Token (as popularized by gastoken.io and later 1inch.exchange's CHI) with an internal liquidity pool, very similar to Uniswap V1.

The LGT's liquidity pool token reserve is implicitly defined as the amount of "unowned" tokens. This allows for very efficient minting and freeing of tokens when combined with ownership transfers.

In addition to the usual mint and free functions LGT offers functions to very efficiently do multiple actions in one transaction:

• mint and sell
• mint and add to liquidity
• buy and free

The full interface can be seen here: ILGT, ILiquidERC20, IERC20

Gas price arbitrage can very easily be realized by minting LGT and directly receiving ether in return in the same transaction. This function is open to every user (and bot ;-)). The amount of received ether can be verified before sending the transaction, giving the minter full control and guaranteeing the arbitrage profit will be fully realised.

Comparative benchmarks for GST2, CHI and LGT. For GST2 and CHI, uniswap is used to do the buying and selling, LGT uses its own liquidity pool.

This does not give a full representation of gas costs, just a snapshot with the used token amounts. Care has been taken that all variables are initialized and the comparison is as fair as possible.

Benchmarks were calculated using a Brownie script on a Ganache forked main net. You can see the script and details here.

GST2: 179564 gas (mint to balance)
 CHI: 180463 gas (mint to balance)
 LGT: 185045 gas (mint to balance)

GST2: 245360 gas (mint and sell)
 CHI: 246548 gas (mint and sell)
 LGT: 183214 gas (mint and sell)

GST2: 609178 gas (free from owned)
 CHI: 599767 gas (free from owned)
 LGT: 598055 gas (free from owned)

GST2: 661449 gas (buy and free)
 CHI: 651093 gas (buy and free)
 LGT: 592585 gas (buy and free)

LGT is optimized to buy or sell tokens in the same transaction they are freed or minted. In these metrics it vastly outperforms the alternatives.

To run tests, clone the repo and use:

brownie test tests/unit/ -C -n auto
brownie test tests/integration/ -n auto --network mainnet-fork

To run the benchmark script:

brownie run benchmarks/gas_token_comparison --network mainnet-fork

The LGT smart contract is deployed on the Ethereum Main Net, Kovan and Ropsten at the address: 0x000000000000C1CB11D5c062901F32D06248CE48.

This repository has not undergone a formal audit. Comments, questions, criticisms and pull requests are welcomed. Feel free to reach out on Gitter.

This project is licensed under the MIT license.