Apparently there was a preferred chalk of mathematicians; but Hagoromo chalk just went out of business. A chemistry professor of one of my classes read an arti

Apparently there was a preferred chalk of mathematicians; but Hagoromo chalk just went out of business. A chemistry professor of one of my classes read an article in some journal bemoaning this, so he decided to pick up and try some while he still could, see what all mathematicians were in to.