If the function has a maximum at , then it has also a local maximum at .

The function has a local minimum at if there exists such that for any .

If a differentiable function has a local minimum or local maximum at , then its partial derivatives are zero at .

If is a critical point of the function and the principal minors of the Hessian are and , then has a local maximum at .

In an orthonormal system the vectors are all unit vectors.

A random variable is discrete, if the set of output values is finite.

The conditional probability is the probability that the event occurs, given that the event occurs.

The function has a minimum at , if for any .

For any and one has .

If the function has a minimum at , then it has also a local minimum at .