Post #3078244

My favorite Pi Day thought this year comes from a question I saw online: Is π a complex number? Of course π is a real number, and every real number is also a complex number. Still, almost nobody casually says “π is a complex number.” In the same spirit, I wouldn’t normally say π is a quaternion either. It’s a funny situation: math is supposed to be as rigorous as possible, yet in ordinary language we hesitate to say some perfectly correct things. I’m happy to write \pi \in \mathbb{C}, but the English sentence “π is a complex number” somehow feels a little strange.