Diophantine equation
A Diophantine equation is an equation which must be solved using only integers. For instance, the Diophantine equation
has infinitely many solutions, two of which are 
and 
.
Finding the solution or solutions to a Diophatine equation is closely tied to modular arithmetic and number theory. Often, when a Diophantine equation has infinitely many solutions, parametric form is used to express the relation between the variables of the equation.
