hardy spaces on homogeneous groups mn 28 volume 2

racterization involves atomic decompositions. An \( H^p \)-atom is a function \( a \) supported on a ball \( B \subset G \) satisfying: \( \|a\|_{L^\infty} \leq |B|^{-1/p} \), \( \int a(g) \, dg = 0 \)