Let $(\Gamma,\leq)$ be a complete lattice and put $\bigwedge_{x\in \Gamma}x =0$. Assume $A$ and $B$ are two subsets of $\Gamma$ with $a\wedge b=0$ for every $a\in A$ and $b\in B$. Q. True or false: $$\bigwedge\{ a\vee b : a\in A , b\in B\}\leq (\bigwedge_{a\in A}a)\vee(\bigwedge_{b\in B}b) $$