lb trading

ntarsis passed his HRT interview and has started his internship. he’s tasked with arbing BTC between two exchanges. he first observes the orderbook for BTC/USD on each exchange. identifying that these two orderbooks represent the same thing was a nonissue; he didn’t even consider it. BTC is BTC everywhere.

ntarsis is then tasked with arbing markets between kalshi and polymarket. he cannot make the same assumptions he made with BTC. market X on kalshi and market Y on polymarket may be such that X=Y, but this mapping is not well defined. market ids, symbols, slugs, rules, etc., all may differ.

an easy solution would be to dump two markets’ metadata to an LLM. in an environment where any false positives are costly, this easy solution would get ntarsis fired.

help ntarsis get a return offer by creating a function that takes as input a market id from kalshi/polymarket and deterministically outputs the market id for the equivalent market on the other exchange, or false if one doesn’t exist.