Average Dimension of Shift Spaces

Recently the author obtained a series of sharp estimates of convolution classes by spaces of shifts of a single function. Those estimates generalize the well-known classical inequalities of Favard, Akhiezer and Krein. In the present paper we compute the average dimension of shift spaces. It appears that this dimension coincides with the average dimension of the spaces of entire functions of exponential type and of equidistant splines.