(p,q)-Calculus

-calculus is a two-parameter extension of q-calculus based on the -derivative of a function , defined by

for and . At , is defined to be when this derivative exists. On monomials,

The quantity is called a twin-basic number. Setting gives the q-derivative, while the limit gives the ordinary derivative. Associated -integrals, Taylor formulas, and an analogue of the fundamental theorem of calculus can also be defined (Njionou Sadjang 2018).