By Gerald Erichsen. There are few things more confusing for beginning Spanish students, at least those who have English as their first language, than learning the differences between ser and estar. After all, they both mean to be in English.I'm not using the terms in a grammatical sense here.) Ser tells you what something is, the nature of its being, while estar refers more to what something does. I might use soy (the first-person present of ser) to tell you what I am, but I'd use estoy (the first-person present of estar) to tell you what I am being.
In mathematics, a quadratic form is a homogeneous polynomial of degree two in a number of variables. For example, + â is a quadratic form in the variables x and y.
Quadratic differential, a form on a Riemann surface that locally looks like the square of an abelian differential. Quadratic form, a homogeneous polynomial of degree two in a number of variables. Quadratic programming, a special type of mathematical optimization problem.