Angle Bracket. An angle bracket is the combination of a bra and ket (bra+ket = bracket) which represents the inner product of two functions or vectors (or 1-forms), in a function space, or. in a vector space. Here, represents the adjoint. The expression is also commonly used to denote the expectation value of a variable .
Definition: In the ancient Peloponnese, Helots were area residents exploited, like the proverbial serf, by the ancient Spartans. The origins of the helots are disputed. One theory is that when the Spartans realized they needed more arable land they looked to the southwest to the more fertile soil of Messenia. The helots were conquered Laconians whom the Spartans made subservient.
Lancelot was the main character in a story in Chretien's The Knight of the Cart. In Chretien's books in the 1100s, Lancelot is described as a skilled knight and conquers many challenges. It is also believed that Lancelot was a folk tale hero.