Reverse Turing test a computer is then said to "pass the Turing test" if it is also judged human. Any of these roles may be changed to form a "reverse Turing test". Arguably the standard form of the reverse Turing test is one in which the subjects attempt to appear to be a computer rather than a human. A formal reverse Turing test follows the same format as a Turing test. Human subjects attempt to imitate the conversational style of a conversation program such as ELIZA. Doing this well involves deliberately ignoring, to some degree, the meaning of the conversation that is immediately
Characteristic class Characteristic class In mathematics, a characteristic class is a way of associating to each principal bundle "X" a cohomology class of "X". The cohomology class measures the extent the bundle is "twisted" — and whether it possesses sections. Characteristic classes are global invariants that measure the deviation of a local product structure from a global product structure. They are one of the unifying geometric concepts in algebraic topology, differential geometry, and algebraic geometry. The notion of characteristic class arose in 1935 in the work of Eduard Stiefel and Hassler Whitney about vector fields on manifolds. Let "G" be a topological