The 2014 paper "Iteration-Free Computation of Gauss--Legendre Quadrature Nodes and Weights" by I. Bogaert (https://doi.org/10.1137/140954969) contains the following expression in Appendix A:
What is the meaning of the "LL" here? It is not defined in the body of the paper and it's such a commonly occurring character sequence that Googling for it has proven futile.

\LLlatex macro, but they forgot\\? – Kirill Mar 16 '18 at 15:09LL. (I refrain from commenting on the effect of publisher copy-editing on mathematical correctness and merely remark that a general strategy for such -- and similar -- cases is to try to find a preprint and see if it the formula is clearer there: a preprint is usually updated if serious mathematical typos are found in press, but a published paper is rarely corrected unless the author takes the blame.) – Christian Clason Mar 16 '18 at 15:17LLsymbol does not appear. – Anton Menshov Mar 16 '18 at 21:15