Specialization is considered key to economic efficiency based on theoretical and empirical considerations. However, the cosmological constant remained a subject of theoretical and empirical interest. Feminist theory is the extension of feminism into theoretical or philosophical fields. It is a theory in theoretical computer science. A third major effort in theoretical particle physics is string theory. The Phillips curve started as an empirical observation in search of a theoretical explanation. Computational linguistics has both theoretical and applied components. Research into string theory has been encouraged by a variety of theoretical and experimental factors. There are several advantages to using smoothed best response, both theoretical and empirical. These theoretical perspectives influence instructional design. Such education combines teaching of both practical skills and theoretical expertise. Supersymmetry appears in many related contexts of theoretical physics. Its fields can be divided into theoretical and practical disciplines. Often these measurements provide insights relevant to theoretical models. Salam contributed to developments in theoretical and particle physics.