document.write("« An AMG saddle point preconditioner with application to mixed Poisson problems on adaptive quad/cube meshes. (arXiv:1901.05830v1 [math.NA])");document.write(" | ");document.write("An explicit relation between knot groups in lens spaces and those in $S^3$. (arXiv:1602.05884v2 [math.GT] UPDATED) »");