For any 0 < ϵ < 1, p ≥ 1 and each function one can find a function with mesx ∈ [0,1): g ≠ f < ϵ such that its greedy algorithm with respect to the Walsh system converges uniformly on [0,1) and the sequence is decreasing, where is the sequence of Fourier coefficients of g with respect to the Walsh system.
@article{bwmeta1.element.bwnjournal-article-doi-10_4064-sm198-2-6, author = {Martin Grigoryan}, title = {Uniform convergence of the greedy algorithm with respect to the Walsh system}, journal = {Studia Mathematica}, volume = {196}, year = {2010}, pages = {197-206}, zbl = {1203.42046}, language = {en}, url = {http://dml.mathdoc.fr/item/bwmeta1.element.bwnjournal-article-doi-10_4064-sm198-2-6} }
Martin Grigoryan. Uniform convergence of the greedy algorithm with respect to the Walsh system. Studia Mathematica, Tome 196 (2010) pp. 197-206. http://gdmltest.u-ga.fr/item/bwmeta1.element.bwnjournal-article-doi-10_4064-sm198-2-6/