Particle-hole–like symmetry and valley degeneracy splitting in graphene dot and antidot L. Villegas-Lelovsky, A. C. Dias, R. Gargano and Fanyao Qu EPL, 111 3 (2015) 38002 Published online: 20 August 2015 DOI: 10.1209/0295-5075/111/38002