Less-than sign Less-than sign The "less-than sign" is a mathematical symbol that denotes an inequality between two values. The widely adopted form of two equal-length strokes connecting in an acute angle at the left, <, has been found in documents dated as far back as the 1560s. In typical mathematical usage, the less-than sign is typically placed between the two values being compared and signals that the first number is less than the second number. Examples of typical usage include "½ < 1" and "−2 < 1". Since the development of computer programming languages, the less-than sign and the greater-than sign have
Degrees of freedom Degrees of freedom In many scientific fields, the degrees of freedom of a system is the number of parameters of the system that may vary independently. For example, a point in the plane has two degrees of freedom for translation: its two coordinates; a non-infinitesimal object on the plane might have additional degrees of freedoms related to its orientation. In mathematics, this notion is formalized as the dimension of a manifold or an algebraic variety. When "degrees of freedom" is used instead of "dimension", this usually means that the manifold or variety that models the system is only implicitly defined.