Martingale Transforms between Martingale Hardy-amalgam Spaces

We discuss martingale transforms between martingale Hardy-amalgam spaces H p , q s , Q p , q and P p , q . Let 0 < p < q < ∞ , p 1 < p and q 1 < q and let f = f n , n ∈ ℕ be a martingale in P p 1 , q 1 ; then, we show that its martingale transforms are the martingales in P p , q for some p , q and similarly for H p , q s and Q p , q .

Maximal Inequalities of Noncommutative Martingale Transforms

In this paper, we investigate noncommutative symmetric and asymmetric maximal inequalities associated with martingale transforms and fractional integrals. Our proofs depend on some recent advances on algebraic atomic decomposition and the noncommutative Gundy decomposition. We also prove several fractional maximal inequalities.