C onsequence am dle oLet∑={A,=AVB}, we have∑hB oLet∑={A,A→B}, we have∑hB o Let 2={-A}, we have∑h(A→B)Consequence . Example . . 1. Let Σ = {A, ¬A ∨ B}, we have Σ |= B. 2. Let Σ = {A, A → B}, we have Σ |= B. 3. Let Σ = {¬A}, we have Σ |= (A → B). Yi Li (Fudan University) Discrete Mathematics April 23, 2013 5 / 25