Q4 b division

Nave Tal 22 Dec 2016 12:56

K1, K2 are said to be positive definite, though that does not mean that $\forall x,z. K_{2}(x,z)\ne 0$. So it's possible that for some {x,z}, $K_{2}(x,z)=0$ and then $K(x,z)=\frac{K_{1}(x,z)}{K_{2}(x,z)}=\frac{K_{1}(x,z)}{0}$ which means K isn't defined for these input.

Should we assume for this section that $\forall x,z. K_{2}(x,z) \ne 0$?