I Built a Tool That Finds Mathematical Arbitrage on Polymarket — Here's How It Works

Prediction markets are supposed to be efficient. They're not. Here's a trade I found last week: the Lebanon Parliamentary Election had 21 candidate markets on Polymarket. Each one was a binary YES/NO bet on whether that party wins the most seats. Exactly one party will win — so the probabilities must sum to 1.0. They summed to 0.789 . That means you could buy one share of YES on every single candidate for $0.789 total, and guaranteed receive $1.00 when the election resolves. No forecasting requi