Q$4$: Let $f$:$\{0,1{\}}^n\{0,1{\}}^m$ and $g$:$\{0,1{\}}^n\{0,1{\}}^m$ be both collision

resistant functions. Let's define $F$:$\{0,1{\}}^{2n}\{0,1{\}}^{2m}$ as $F(x_1,x_2)=f$

$(x_1)||g(x_2).$

Would $F$ still be a collision resistant hash function? Would $F$ be a

one$-$way function? $(5$ points each$)$