| English | Russian |
| in a first approximation | в первом приближении (аппроксимации; The following expressions are obtained to a first approximation in z.) |
| the first term does not exceed a in modulus | первый член не превосходит а по модулю |
| we denote by P the projector in H onto the space spanned by n first eigenvectors of A | пространство, натянутое на n первых собственных векторов A |