Khotyakov, MikhailMichelangeli, Alessandro2015-02-132015-02-132015https://openscience.sissa.it/handle/1963/34443This is an accurate translation from Russian and adaptation to the modern mathematical jargon of a classical paper by M. Sh. Birman published in 1956, which is still today central in the theory of self-adjoint extensions of semi-bounded operators, and for which yet no English version was available so far.enTranslation and adaptation of Birman's paper "On the theory of self-adjoint extensions of positive definite operators" (1956)Preprint