# loop

In mathematics, the term loop' may refer to any of the following:

• A knot or hitch that holds its form.

• A degenerate edge of a graph that joins a vertex to itself.

• A sequence of instructions that is repeated either a specified number
of times or until a particular condition prevails. Loops lie at the
heart of most computer programs. The most common type is the **iterative
loop**, signified by keywords such as *for*, *while*, *do*, and *repeat*, or their equivalent, in which a given
set of instructions is repeated a specified number of times. The **recursive
loop** is a more powerful construct that carries out a given
set of instructions, typically including recursive calls with modified parameters back to the instruction set itself, until
a terminating condition is met. Recursive algorithms solve problems
by reducing them to smaller and smaller subproblems until a solution
is found, reusing the same set of instructions as often as needed.