 However, according to the semantic approach, \(K\varphi\) holds in those worlds from which all epistemically accessible situations satisfy \(\varphi\), so \(\llbracket K p \rrbracket^{M} = \left\{ w_1 \right\}\). Thus, \({K'}\) and K are not equivalent. One of the reasons for this mismatch is that the two options do not enforce the same properties on the derived notion of knowledge. For example, while the semantic approach enforces negative introspection (by making \(R_K\) an equivalence relation), the syntactic one does not. In fact, this property fails at \(w_3\), as \(\lnot {K'p}\) is true \(({B p} \land p\) fails, as p fails) but still \(K'\lnot{K'p}\) (unfolded as \({B (\lnot {B p} \lor \lnot p)} \land (\lnot B p \lor \lnot p))\) is  false.[3]