Not to be confused with group presentation. Representation theory is a branch of mathematics that studies abstract algebraic structures by representing their elements as linear transformations of vector spaces, and studies modules over these abstract algebraic structures.
The signature effect of HIV infection, and the cause of AIDS, is disruption of the T-lymphocyte branch of the immune system and in particular the destruction of CD4+ T-helper cells.
The HIV virus attacks T-helper cells, or CD4+ cells, by fitting itself into the cell like a key in a lock. Once it has invaded, it can use its own RNA as a template to make copies of itself, multiplying and traveling through the body.