Search results for "Automorphic function"
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The Khuri-Jones Threshold Factor as an Automorphic Function
2013
The Khuri-Jones correction to the partial wave scattering amplitude at threshold is an automorphic function for a dihedron. An expression for the partial wave amplitude is obtained at the pole which the upper half-plane maps on to the interior of semi-infinite strip. The Lehmann ellipse exists below threshold for bound states. As the system goes from below to above threshold, the discrete dihedral (elliptic) group of Type 1 transforms into a Type 3 group, whose loxodromic elements leave the fixed points 0 and $\infty$ invariant. The transformation of the indifferent fixed points from -1 and +1 to the source-sink fixed points 0 and $\infty$ is the result of a finite resonance width in the im…
The structure of symplectic groups associated with a quadratic extension of fields
2003
Given a quadratic extension L/K of fields and a regular alternating space (V, f) of finite dimension over L, we determine the isometry group of a K-subspace W of V which does not split into the orthogonal sum of two proper K-subspaces, W being neither an L-space nor a K-substructure.