n. cohomology theory
homology theory
atomic theory
auteur theory
big bang theory
Bohr theory
catastrophe theory
cell theory
chaos theory
conspiracy theory
decision theory
devil theory
domino theory
field theory
Galois theory
game theory
gauge theory
general theory of relativity
germ theory
grand unified theory
grand unification theory
graph theory
group theory
information theory
kinetic theory
kinetic theory of gases
kinetic theory of heat
knot theory
number theory
quantity theory
quantum field theory
quantum theory
queer theory
set theory
special theory of relativity
steady state theory
string theory
theory of games
theory of numbers
trickle down theory
undulatory theory
wave theory