ERC20 invariant concept and implementation survey

## Summary
> Please give a short summary of this research topic.

The ERC-20 token standard is widely used, but it does have certain limitations. Consequently, several modified versions of the ERC-20 token have emerged. We anticipate your research on these token standards to explore their respective advantages and disadvantages.

## Description
> Please provide a detailed description to the topic.

Many proposals seek to enhance the existing ERC-20 standard, including ERC-233, ERC-677, ERC-777, ERC-1363, and more. These proposals address various issues encountered with ERC-20 tokens. The implementation details among different types of ERC standards vary based on their specific objectives and features. It is essential to research each standard individually to understand the problems they aim to solve and their implementation details.

## Source
> Please provide related resource for the topics, including articles, research papers and more.

[ERC-233](https://github.com/Dexaran/ERC223-token-standard)

[ERC-677](https://github.com/ethereum/EIPs/issues/677)

[ERC-777](https://ethereum.org/zh-tw/developers/docs/standards/tokens/erc-777/)

[ERC-1363](https://www.rareskills.io/post/erc-1363)

## Others
> Please provide more information if there is any.

None