Abstract
Various variational approaches are derived from the least norm variational principle. The application of these approaches to the elastic scattering of electrons and positrons by atomic hydrogen shows that the corresponding phaseshifts are related to each other and agree very well with the results of other authors. A test for Kanellopoulos' inequality (1972, 1975) provides us with effective upper and lower bounds for the S-wave phaseshifts of e--H elastic scattering (singlet-state).