评估此合金表达

Question

如何评估此合金表达式？

^{y0->y1->y1, y0->y2->y0, y1->y0->y1, y2->y0->y0, y2->y1->y2, y2->y2->y1}[y]

Answer 1

{y0->y1, y0->y0, y1->y1}