Circumference
131Comparison of Canadian and American football — Canadian and American football are very similar, as both have their origins in rugby. As such, the rules of these sports are very similar, although a comparison illustrates some key differences.HistoryFootball was introduced to North America in… …
132Planar algebra — In mathematics, planar algebras first appeared in the work of Vaughan Jones on the standard invariant of a II1 subfactor [http://www.math.berkeley.edu/ vfr/plnalg1.ps] . They also provide an appropriate algebraic framework for many knot… …
