Monotone difference schemes for equations with mixed derivative

There are considered elliptic and parabolic equations of arbitrary dimension with alternating coefficients at mixed derivatives. For such equations monotone difference schemes of the second order of local approximation are constructed. Schemes suggested satisfy the principle of maximum. A priori estimates of stability in the norm $С$ without limitation on the grid steps $\tau$ and $h_\alpha$, $\alpha=l,2,\dots,p$ are obtained (unconditional stability).