1. R. N. Sen andH. Umezawa:Limitations on the Spontaneous Breakdown of Symmetries, reported at theColloquium on l’Extension du Groupe de Poincaré aux symétries internes des Particules Elémentaires, Gif-sur-Yvette (S-et-O.) (April 1966). A detailed account will be published elsewhere.
2. L. Leplae, R. N. Sen andH. Umezawa:Problems of Fundamental Physics, (Kyoto, 1965), p. 673; also published asProgr. Theor. Phys. Suppl., Extra Number (1965).
3. A detailed study of such B-E condensations has been made byH. Ezawa:Journ. Math. Phys.,6, 380 (1965); see alsoH. Araki andE. J. Woods:Journ. Math. Phys.,4, 637 (1963).
4. W. Heisenberg:Zeits. Naturforsch.,14a, 441 (1959); earlier works are cited there.
5. This remarkable aspect of the dynamical rearrangement has already been noticed in several examples. See ref. (5–7).