Fine group gradings of the real forms of $sl(4,\C)$, $sp(4,\C)$, and   $o(4,\C)$
  We present an explicit description of the 'fine group gradings' (i.e. group gradings which cannot be further refined) of the real forms of the semisimple Lie algebras $sl(4,\C)$, $sp(4,\C)$, and $o(4,\C)$. All together 12 real Lie algebras are considered, and the total of 44 of their fine group gradings are listed.   The inclusions $sl(4,\C)\supset sp(4,\C)\supset o(4,\C)$ are an important tool in our presentation. Systematic use is made of the faithful representations of the three Lie algebras by $4\times 4$ matrices. 
Ji\v{r}\'i Patera, Edita Pelantov\'a, Milena Svobodov\'a