https://hdl.handle.net/1721.1/18164 Sun, 12 Apr 2026 20:25:55 GMT 2026-04-12T20:25:55Z https://hdl.handle.net/1721.1/26691 Topologies of group algebras and a theorem of Littlewood Helgason, Sigurdur 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 Tue, 01 Jan 1957 00:00:00 GMT https://hdl.handle.net/1721.1/26691 1957-01-01T00:00:00Z https://hdl.handle.net/1721.1/26690 Response to Steele Prize Award Helgason, Sigurdur First published in the Notices of the American Mathematical Society in Vol.35, 1988, published by the American Mathematical Society Fri, 01 Jan 1988 00:00:00 GMT https://hdl.handle.net/1721.1/26690 1988-01-01T00:00:00Z https://hdl.handle.net/1721.1/26689 Invariant differential equations on homogeneous manifolds Helgason, Sigurdur First published in the Bulletin of the American Mathematical Society in Vol.83, 1977, published by the American Mathematical Society Sat, 01 Jan 1977 00:00:00 GMT https://hdl.handle.net/1721.1/26689 1977-01-01T00:00:00Z https://hdl.handle.net/1721.1/26688 Paley-Wiener theorems and surjectivity of invariant differential operators on symmetric spaces and Lie groups Helgason, Sigurdur First published in the Bulletin of the American Mathematical Society in Vol.79, 1973, published by the American Mathematical Society Mon, 01 Jan 1973 00:00:00 GMT https://hdl.handle.net/1721.1/26688 1973-01-01T00:00:00Z https://hdl.handle.net/1721.1/26687 A Fatou- type theorem for harmonic functions on symmetric spaces Helgason, Sigurdur First published in the Bulletin of the American Mathematical Society in Vol.74, 1968, published by the American Mathematical Society Mon, 01 Jan 1968 00:00:00 GMT https://hdl.handle.net/1721.1/26687 1968-01-01T00:00:00Z https://hdl.handle.net/1721.1/26686 Radon-Fourier transforms on symmetric spaces and related group representations Helgason, Sigurdur First published in the Bulletin of the American Mathematical Society in Vol.71, 1965, published by the American Mathematical Society Fri, 01 Jan 1965 00:00:00 GMT https://hdl.handle.net/1721.1/26686 1965-01-01T00:00:00Z https://hdl.handle.net/1721.1/26685 A duality in integral geometry; some generalizations of the Radon transform Helgason, Sigurdur First published in the Bulletin of the American Mathematical Society in Vol.70, 1964, published by the American Mathematical Society Wed, 01 Jan 1964 00:00:00 GMT https://hdl.handle.net/1721.1/26685 1964-01-01T00:00:00Z https://hdl.handle.net/1721.1/26684 Duality and Radon transform for symmetric spaces Helgason, Sigurdur First published in the Bulletin of the American Mathematical Society in Vol.69, 1963, published by the American Mathematical Society Mon, 01 Jul 1963 00:00:00 GMT https://hdl.handle.net/1721.1/26684 1963-07-01T00:00:00Z https://hdl.handle.net/1721.1/26683 Fundamental solutions of invariant differential operators on symmetric spaces Helgason, Sigurdur First published in the Bulletin of the American Mathematical Society in 1963, published by the American Mathematical Society Tue, 01 Jan 1963 00:00:00 GMT https://hdl.handle.net/1721.1/26683 1963-01-01T00:00:00Z https://hdl.handle.net/1721.1/26682 Some results on invariant theory Helgason, Sigurdur First published in the Bulletin of the American Mathematical Society in Vol.68 1962, published by the American Mathematical Society Mon, 01 Jan 1962 00:00:00 GMT https://hdl.handle.net/1721.1/26682 1962-01-01T00:00:00Z