PageHeader : Punkcialaj Ekvacioj, 45 (2002) 23-51 Title : On $L^{p}$ Regularity for Weak Derivatives of Spherically Title : Symmetric Solutions of the Porous Media Equation AuthorInfo : By AuthorInfo : Kazuya HAYASIDA and Masatomo KOBAYASHI AuthorInfo : (Kanazawa University and NEC Communication Systems LTD., Japan) section : 1. Introduction section : 2. Results section : 3. Preliminaries section : 4. Lemma 4.1 and its proof section : 5. The first $L^{p}$ estimate section : 6. Lemma 6.1 and its proof section : 7. The second $L^{p}$ estimate section : 8. Proof of results section : References