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phildaian

Re:Trading bots are running wild on cryptocurrency exchanges on Wednesday April 17, 2019 @05:29PM (#19686647)
If you find something wrong with it, consider this an open offer for me to revise or withdraw the paper as a result.

That being said, I've been studying blockchains for years, and this paper has been reviewed by some very high caliber designers of blockchain protocols in both academia and industry. It also uses very simple models as in http://randomwalker.info/publications/mining_CCS.pdf which in my view are extremely unlikely to be incorrect (of course, anything is possible).

Well, we show (among many other results) that today's system is potentially unstable assuming miners are rational and profit maximizing. I don't think that's paranoia in a system that gives you 0 security guarantees unless you assume miners are rational and profit maximizing.

> Virtually all existing market designs are crappy. Maybe CBOT is an exception. Michael Lewis' book is a big giant marketing document for a shitty market design, FWIIW: not a preconception; I read and panned his ridiculous book.

I'm not saying anything promoted by Lewis is a good market design, nor that existing continuous limit order books are. Merely that from the PoV of the efficient markets hypothesis, blockchain markets are worse (and have the potential to be better, e.g. by exploring batched designs).

I'm not saying he has preconceptions about the book, I'm saying his opinion of the book is creating unwarranted preconceptions about our work.

The paper doesn't comment on money markets much at all, and cites pretty unambiguous peer reviewed work which is highly substantiated when it does.

Yes, the people who created DEXes do know about and advertise this issue, because this is work we've been doing since early 2017 and discussing with them even earlier. In fact, I advise a lot of those projects, and many consider me the SME on DEX frontrunning. I'm also the reason 0x e.g. released a bot to explicitly do this.

To claim this is what they were designing for is just ignorance of the space though. None of them knew about or even anticipated this issue; just because it is obvious to you does not mean it was obvious to them.

Just because DEXes are only for regulatory arbitrage (your words, not mine) doesn't mean that we should stand up crappy market designs.

The majority of the paper is about the formalization of and data on PGAs and miner OO, which was also not known in the blockchain community until now. If you point me to a reference to the contrary, or that contains the same results as e.g. Sections 5-7 of our paper, I'll gladly cite this and reduce my claims of novelty. Otherwise, this is something I've been working on for years, I'm going to stick with it, and it's up to peer review in the scientific community to decide :).

I hear what you are saying, but your preconceptions about Flash Boys being a bad book seem to be severely coloring your understanding of the work!

I linked you to several sources for my definitions and you haven't commented on any of them, so no idea how you could reach that conclusion. I've explained to you that even with your restrictive definition, our paper covers analogous behavior in DEXes.

Yes, it's very surprising, no, shocking, that people on Wall St. are reluctant to have behaviors like this called out publicly....

I am not Michael Lewis and cannot speak to the accuracy of his facts; our work is a scientific paper backed by a lot of data currently undergoing peer review. The views on HFT and market design in the paper are similarly informed by cited work that is quite extensive in its data analysis, and peer reviewed. I recommend you read it!

Author of the paper here. I justified our use of the word "frontrunning" on a Twitter thread: https://twitter.com/phildaian/status/1116698738343460864

There are a few different points here. Firstly, there are plenty of unambiguous definitions of frontrunning that are accepted by the scientific community that this blatantly does fall under; see the Clark SoK we cite in our paper for this in the blockchain space, or the definition Wikipedia uses, which was from an economics article by Khan & Lu (https://papers.ssrn.com/sol3/papers.cfm?abstract_id=1140694): "trading by some parties in advance of large trades by other parties, in anticipation of profiting from the price movement that follows the large trade."

The second point here is even if you want to restrict the definition to require privileged information, privilege in p2p networks is not binary: there are some nodes that are better peered on the topology, have better mining equipment, etc. who can use these privileges to extract market rent, harming the security of a blockchain.

This is a complex and dense paper that took 8 people 18 months to produce, and I recommend you read it with an open mind, rather than having a gut reaction to whether we use your preferred definition of "frontrunning". I also recommend reading the primary source material directly, or at least my summary on Twitter - https://twitter.com/phildaian/status/1116155236433956865

Happy to answer any questions!

Great explanation! For an in depth and relatively formal (and mathematical) look at this from an economist I recommend https://faculty.chicagobooth.edu/eric.budish/research/HFT-Fr...