Mathematicians give a third answer on the vertical axis, "That question is poorly defined, but we have a sub-field devoted to every plausible version of it."

"Research Areas by Size and Countedness", by Randall Munroe, licensed under Creative Commons Attribution-NonCommercial 2.5 License

Alt Text

Mathematicians give a third answer on the vertical axis, "That question is poorly defined, but we have a sub-field devoted to every plausible version of it."