C onsequence am dle oLet∑={A,=AVB}, we have∑hB oLet={A,A→B}, we have∑hB oLet∑={-A}, we have∑(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 24, 2012 5 / 25