| Subject | English | Catalan |
| math. | ballot theory | teoria de l'escrutini |
| math. | catastrophe theory | teoria de les catàstrofes |
| math. | decision theory | teoria de la decisió |
| environ. | economic theory The study of relationships in the economy. Its purpose is to analyze and explain the behaviour of the various economic elements. The body of economic theory can be divided into two broad categories, positive theory and welfare theory. Positive theory is an attempt to analyze the operation of the economy without considering the desirability of its results in terms of ultimate goals. Welfare theory is concerned primarily with an evaluation of the economic system in terms of ethical goals which are not themselves derived from economic analysis | teoria econòmica |
| math. | frequency theory of probability | teoria de probabilitat freqüentista |
| math. | fuzzy set theory | teoria de conjunts borrosos |
| math. | game theory | teoria de jocs |
| math. | higher-order asymptotic theory | teoria asimptòtica d'ordre superior al primer |
| math. | information theory | teoria de la informació |
| math. | Lexis theory | teorema de Lexis |
| math. | Neyman-Pearson theory | teoria de Neyman-Pearson |
| math. | renewal theory | teoria de renovació |
| math. | single factor theory | teoria d'un sol factor |
| environ. | systems theory The science concerned with the general study of structures and behaviours of systems which may be applicable in different branches of learning | teoria de sistemes |
| environ. | theory of money A coherent group of general propositions about the supply and demand of money, interest rates, the flow of money's influence on the overall economy or the policies that should be adopted by institutions controlling the money supply | teoria del diner |
| environ. | theory of the environment A structured simulation or explanation based on observation, experimentation and reasoning that seeks to demonstrate, characterize or explain the actions and interactions of the total surrounding conditions of a given system | teoria del medi ambient |
| environ. | theory of the welfare state A political conception of government in a capitalist economy where the state is responsible for insuring that all members of society attain a minimum standard of living through redistribution of resources, progressive taxation and universal social programs, including health care and education | teoria de l'estat del benestar |
| math. | two-factor theory | teoria de dos factors |
| math. | utility theory | teoria de la utilitat |