'established a theory' is correct and usable in written English.
You can use it when you want to refer to a specific hypothesis or idea that someone has created. For example: "Einstein established a theory that changed the way we think about the nature of time."
He established a theory of international trade that is now known as the Heckscher-Ohlin theory.
He thus established a theory of valency (1852), which became the basis of modern structural chemistry.
In 1855, Rudolf Virchow established a theory on coagulation [1].
García-Cuerva [25] and Strömberg-Torchinsky [26] established a theory of weighted Hardy spaces on (mathbb{R}^{n}).
For manipulating heat flow efficiently, recently we established a theory of temperature-dependent transformation thermotics which holds for steady-state cases.
For this purpose, the authors established a theory of variable exponent spaces of Clifford-valued functions with applications to homogeneous and nonhomogeneous A-Dirac equations; see also [25, 26].
He believed that careful observation and talking at length with patients, often over long walks were vital to establishing a theory.
To establish a theory of solutions, it is necessary to construct a theoretical (or semitheoretical) equation for the excess Gibbs energy as a function of absolute temperature (T ) and the mole fractions x1 and x2.
First, should we attempt to establish a theory of persistence, and then let this dictate our theory of time?
Thus, we need to establish a theory that allows us to handle systematically both time scales simultaneously.
In passing, we establish a theory of moderate dimension growth for AH algebras, the existence of which was first supposed by Blackadar.
