73,754 research outputs found
Koszul differential graded algebras and BGG correspondence
The concept of Koszul differential graded algebra (Koszul DG algebra) is
introduced. Koszul DG algebras exist extensively, and have nice properties
similar to the classic Koszul algebras. A DG version of the Koszul duality is
proved. When the Koszul DG algebra is AS-regular, the Ext-algebra of
is Frobenius. In this case, similar to the classical BGG correspondence,
there is an equivalence between the stable category of finitely generated left
-modules, and the quotient triangulated category of the full triangulated
subcategory of the derived category of right DG -modules consisting of all
compact DG modules modulo the full triangulated subcategory consisting of all
the right DG modules with finite dimensional cohomology. The classical BGG
correspondence can derived from the DG version.Comment: 29 page
Massive Complex Scalar Field in a Kerr-Sen Black Hole Background: Exact Solution of Wave Equation and Hawking Radiation
The separated radial part of a massive complex scalar wave equation in the
Kerr-Sen geometry is shown to satisfy the generalized spheroidal wave equation
which is, in fact, a confluent Heun equation up to a multiplier. The Hawking
evaporation of scalar particles in the Kerr-Sen black hole background is
investigated by the Damour-Ruffini-Sannan's method. It is shown that quantum
thermal effect of the Kerr-Sen black hole has the same characteras that of the
Kerr-Newman black hole.Comment: Revtex, 5 pages, no figure, submitted to Phys. Rev.
Sending multiple RTP streams in a single RTP session
This memo expands and clarifies the behavior of Real-time Transport Protocol (RTP) endpoints that use multiple synchronization sources (SSRCs). This occurs, for example, when an endpoint sends multiple RTP streams in a single RTP session. This memo updates RFC 3550 with regard to handling multiple SSRCs per endpoint in RTP sessions, with a particular focus on RTP Control Protocol (RTCP) behavior. It also updates RFC 4585 to change and clarify the calculation of the timeout of SSRCs and the inclusion of feedback messages
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