The function \( L(w) = w^2 - 2mw + m^2 + 4 \) is a quadratic in \( w \). The minimum occurs at \( w = \frac2m2 = m \), since the vertex of \( aw^2 + bw + c \) is at \( w = -b/(2a) \), here \( a = 1 \), \( b = -2m \), so: - Crosslake