Right-angled Artin subgroups of the $C^{\infty}$ diffeomorphism group of   the real line
  We prove that every right-angled Artin group embeds into the $C^{\infty}$ diffeomorphism group of the real line. As a corollary, we show every limit group, and more generally every countable residually RAAG group, embeds into the $C^{\infty}$ diffeomorphism group of the real line. 
Hyungryul Baik, Sang-hyun Kim, and Thomas Koberda
math.GT math.GR