Why does Figure 2.F.1(b) (MWG page 30) satisfy the WARP (Definition 2.F.1)?
Intuitively, this just says that if the bundle you choose was possible under wealth $w$ and price $p$ but it is not $x(p, w)$, then it must be that you cannot obtain it when price is $p'$ and wealth is $w'$.

It simply does not say anything about case (b) in which $p' \cdot x(p'', w'') &gt; w$ and $p'' \cdot x(p', w') &gt; w''$. Since the first part of the if ... then statement in the definition is false, everything evaluates to true.