Banach spaces, as complete normed vector spaces, form a central framework in modern functional analysis. Their rich geometric structure underpins much of the theoretical development in approximation ...

A threshold autoregressive (TAR) model is an important class of nonlinear time series models that possess many desirable features such as asymmetric limit cycles and amplitude-dependent frequencies.

Greedy bases are those bases where the Thresholding Greedy Algorithm (introduced by S. V. Konyagin and V. N. Temlyakov) produces the best possible approximation up to a constant. In 2017, P. M. Berná ...