Template:Are You Sure/May 9

A flea circus is a circus sideshow attraction in which fleas are attached (or appear to be attached) to miniature carts and other items, and encouraged to perform circus acts within a small housing.

The Human Flea Circus is "similar, but with people instead of fleas."[citation needed

] See also Carnevale Tenebre.]]

• ... that tickets for the Human Flea Circus are being given away free due to COVID-19 lockdown restrictions?

• ... that Jensen's inequality, named after the Danish mathematician Johan Jensen, relates the value of a convex function of an integral to the integral of the convex function; and that in its simplest form the inequality states that the convex transformation of a mean is less than or equal to the mean applied after convex transformation; and that it is a simple corollary that the opposite is true of concave transformations; and that Jensen's inequality generalizes the statement that the secant line of a convex function lies above the graph of the function, which is Jensen's inequality for two points?