show/hide this revision's text 3 added 422 characters in body

Stufe (=level) of a non-real field (wikipedia.de). It is the least number of squares $a_i^2$ such that $\sum_i a_i^2 = -1$, $\infty$ if no such sum exists.

In this paper, the level of a subgroup of $SL_2(\mathcal{O})$ is defined ($\mathcal{O}$ a number field), as the generalisation of the stufe of a field, so the term has been translated, but only in a shift of context.

To pick a random paper, try The stufe of number fields.

show/hide this revision's text 2 added 143 characters in body

Stufe (=level) of a non-real field (wikipedia.de). It is the least number of squares $a_i^2$ such that $\sum_i a_i^2 = -to 1$, $\infty$ if no such sum exists.

To pick a random paper, try The stufe of number fields.

show/hide this revision's text 1 [made Community Wiki]

Stufe (wikipedia.de) - to pick a random paper, try The stufe of number fields.