Let $K$ be a closed, bounded and infinite subset of $\mathbb{C}$. Let $Q$ and $R$ be two non-zero polynomials in $\mathbb{C}[X]$. Show that: $$\|Q\|_K \|R\|_K \geq \|QR\|_K.$$
Let $K$ be a closed, bounded and infinite subset of $\mathbb{C}$. Let $Q$ and $R$ be two non-zero polynomials in $\mathbb{C}[X]$. Show that:
$$\|Q\|_K \|R\|_K \geq \|QR\|_K.$$