On almost everywhere convergence of orthogonal spline projections with arbitrary knots

Markus Passenbrunner, Alexei Shadrin

The main result of this paper is a proof that, for any $f\in L_1[a,b]$, a sequence of its orthogonal projections $(P_{{\Delta }_n}(f))$ onto splines of order $k$ with arbitrary knots $Δ_n…