Mathematics is made of 50 percent formulas, 50 percent proofs, and 50 percent imagination.
"A mathematician is a device for turning coffee into theorems" (P. Erdos)
Addendum: American coffee is good for lemmas.
An engineer thinks that his equations are an approximation to reality. A physicist thinks reality is an approximation to his equations. A mathematician doesn't care.
Old mathematicians never die; they just lose some of their functions.
Mathematicians are like Frenchmen: whatever you say to them, they translate it into their own language, and forthwith it means something entirely different. -- Goethe
Mathematics is the art of giving the same name to different things. -- J. H. Poincare
