d \\to \\mathbb{R} \\) is a continuously differentiable, convex function, then \\( x_0 \\) is a global minimizer if and only if \\( \\nabla f(x_0) = 0 \\).";
                    case 5:
                        return "The text defines an \\( m \\)-strongly convex function \\( f : \\mathbb{R}^d \\to \\mathbb{R} \\) as one satisfying \\( \\nabla^2 f(x) \\succeq mI_{d \\times d} \\), for all \\( x \\in \\mathbb{R}^d \\) and some \\( m > 0 \\).";
                    case 6:
                        return "The t