  In different branches of physics, we frequently deal with vector del operator
($\vec{\nabla}$). This del operator is generally used to find curl or
divergence of a vector function or gradient of a scalar function. In many
important cases, we need to know the parent vector whose curl or divergence is
known or require to find the parent scalar function whose gradient is known.
But the task is not very easy, especially in case of finding vector potential
whose curl is known. Here,'inverse curl', 'inverse divergence' and 'inverse
gradient' operators are defined to solve those problems easily. All operators
are defined in the orthogonal curvilinear co-ordinate system.
