Area of a circle to eight sides and so on. For a polygon with 2"n" sides, the parallelogram will have a base of length "ns", and a height "h". As the number of sides increases, the length of the parallelogram base approaches half the circle circumference, and its height approaches the circle radius. In the limit, the parallelogram becomes a rectangle with width "r" and height "r". There are various equivalent definitions of the constant π. The conventional definition in pre-calculus geometry is the ratio of the circumference of a circle to its diameter: However, because the circumference of a circle is not a
Straight-line grammar definition of the more general formalism of straight-line context-free tree grammars can be found in Lohrey et al. An SLG in Chomsky normal form is equivalent to a straight-line program. Straight-line grammar A straight-line grammar (sometimes abbreviated as SLG) is a formal grammar that generates exactly one string. Consequently, it does not branch (every non-terminal has only one associated production rule) nor loop (if non-terminal "A" appears in a derivation of "B", then "B" does not appear in a derivation of "A"). Straight-line grammars are widely used in the development of algorithms that execute directly on compressed structures (without prior