About 20 years ago, while doing research in algorithms for robot motion planning, we managed to reduce the problem into a…
“About 20 years ago, while doing research in algorithms for robot motion planning, we managed to reduce the problem into a certain property of quadratic curves. It was clear from the examples that both (1) the statement held, and (2) it was likely known in the XIX century. Lo and behold no modern book had the theorem. Eventually we took the plunge and proved the result from scratch. A year later, while perusing in a used bookstore I found the result an 1880s high school textbook. I still have the book in my shelves as a reminder.”