theory (physics), model (physics)
Axiomatizations
Tools
Structural phenomena
Types of quantum field thories
abstract duality: opposite category,
concrete duality: dual object, dualizable object, fully dualizable object, dualizing object
between higher geometry/higher algebra
Langlands duality, geometric Langlands duality, quantum geometric Langlands duality
In string theory a given Riemann surface with punctures can usually be read in different ways as describing either closed strings or open strings. For instance the disk-diagram describes equivalently a process where a closed string disappears, or a process where an open string first appears and then disappears.
Since closed string excitations induce gravity while open string excitations induce Yang-Mills fields as effective field theories, this leads to a multitude of relations between these ordinary quantum field theories, such as the KLT relations or the AdS/CFT correspondence.
J. Khoury, Herman Verlinde, On Open/Closed String Duality (arXiv:hep-th/0001056)
Leonardo Rastelli, Lectures on open/closed string duality (pdf)