broken windows theory;  criminological theory stating that serious crime can be prevented by maintaining the good physical condition of an urban environment
 being prepared for a theoretical (ideological) argument;  being armed with theoretical backing
 music theory;  musical theory
 game theory;  theory of games
 general equilibrium theory
 Gaia theory;  Gaia principle;  Gaia hypothesis
 cryptography;  cryptographic theory
 Modern Monetary Theory;  Modern Money Theory;  neo-chartalism
 renormalization theory;  renormalisation theory
 relational theory of meaning
 discourse representation structure theory;  DRS
 factor proportions theory (of international trade)
 theoretical air fuel ratio
 item response theory;  IRT
 Shannon-Hartley theorem;  Shannon's law
 frontier molecular orbital theory
 discourse representation theory;  DRT
 Maxwell's electromagnetic theory
 macro theory;  macroeconomic theory;  macroscopic theory
 loop quantum gravity;  LQG