http://hdl.handle.net/1721.1/18165 http://hdl.handle.net/1721.1/26691 Topologies of group algebras and a theorem of Littlewood Helgason, S. An important problem in Fourier analysis is that of investigating the relationship between the "size" of a function and the "size" of its Fourier transform. The present paper can be regarded as a contribution to this problem. First published in the Transactions of the American Mathematical Society in Vol.86, 1957, published by the American Mathematical Society http://hdl.handle.net/1721.1/26690 Response to Steele Prize Award Helgason, S. First published in the Notices of the American Mathematical Society in Vol.35, 1988, published by the American Mathematical Society http://hdl.handle.net/1721.1/26689 Invariant differential equations on homogeneous manifolds Helgason, S. First published in the Bulletin of the American Mathematical Society in Vol.83, 1977, published by the American Mathematical Society http://hdl.handle.net/1721.1/26688 Paley-Wiener theorems and surjectivity of invariant differential operators on symmetric spaces and Lie groups Helgason, S. First published in the Bulletin of the American Mathematical Society in Vol.79, 1973, published by the American Mathematical Society