Specific, individually named mathematical objects and structures: particular sets, spaces, numbers, sequences, curves, groups and other constructions that mathematicians study and refer to by name, such as the Mandelbrot set, the Klein bottle, the Fibonacci sequence, Pascal's triangle and the Riemann zeta function. Distinct from Concepts, which record a general class or idea (prime number, manifold) rather than one particular instance of it, and from Theorems and Conjectures, which record a proved or unproven claim about an object rather than the object itself. Belongs here: a specific, individually named mathematical object or structure, grouped below by the branch of mathematics it belongs to. Does not belong here: a general class of objects or an abstract idea, filed under Concepts; a proved statement about an object, filed under Theorems; an unproven claim, filed under Conjectures; and the mathematician who defined or studied the object, filed under Mathematicians.