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| $\mathbf F_1=\frac{-1}{\sqrt{x^2+y^2}}\binom{x}{y},\quad \nabla\cdot\mathbf F_1=-\frac 1r<0$ | $\mathbf F_2=\frac{-1}{x^2+y^2}\binom{x}{y},\quad \nabla\cdot\mathbf F_2=0$ | $\mathbf F_3=\frac{-1}{(x^2+y^2)^{3/2}}\binom{x}{y},\quad \nabla\cdot\mathbf F_3=\frac 1{r^3}>0$ |
| Local and global contraction. | Global contraction. No local expansion/contraction. | Global contraction. Local expansion. |