Application( Cont. Example(Groups) Let C=[, e where is a binary relation and e is a constant symbol. The class of group is described as o Vxe x=xe=x O VXVyVzX·(yz)=(xy)·z, wxyx·y=y.x=eApplication(Cont.) Example (Groups) Let L = {·, e} where · is a binary relation and e is a constant symbol. The class of group is described as 1 ∀xe · x = x · e = x, 2 ∀x∀y∀zx · (y · z) = (x · y) · z, 3 ∀x∃yx · y = y · x = e. Yi Li (Fudan University) Discrete Mathematics June 20, 2012 7 / 15