<p> The binding energy B of a A-particle in infinite nuclear matter has been estimated to be about 30 MeV by extrapolating the observed binding energies of hypernuclei. On the other hand, theoretical estimates so far done by various methods are generally much larger than 30 MeV. Various reasons for this descrepancy have been considered. We estimate the effect of the A-E conversion as one of the effects removing that descrepancy. In order to take account of the A-E conversion explicitly, it is convenient to use the so-called two-channel formalism. We calculate the binding energy B in the two-channel formalism (TCF) as well as in the more conventional one-channel formalism (OCF). It is found that B in the TCF can be substantially smaller than in the OCF. The difference of the values of B in the two formalisms is interpreted as due to the Pauli principle which suppresses the A-E conversion in nuclear matter. The relation between this effect in the TCF and three-bodyANN forces in the OCF is clarified. </p> / Thesis / Master of Science (MSc)