Abstract:
All quasigreedy subsystems of the Haar system in $L^1(0,1)$ are described. The problem of renormalizing the Haar system so that it becomes a quasigreedy basis is also studied.
Keywords:greedy algorithm in $L^1(0,1)$, Haar system, $\omega$-quasigreedy basis, quasigreedy Haar subsystem, Banach space.