Logical Equivelence Definition Two proposition a and B such that, for every valuation v,v(a)=v(e) are called logically equivalent.We denote this by a≡BLogical Equivenlence . Definition . . Two proposition α and β such that, for every valuation V, V(α) = V(β) are called logically equivalent. We denote this by α ≡ β. Yi Li (Fudan University) Discrete Mathematics April 2, 2013 11 / 20