设集合A=﹛a,b,c,d,e﹜上有一个分划,S=﹛﹛a,b﹜,﹛c﹜,﹛d,e﹜﹜...答:A上的等价关系R=SXS={( a,a), (a,b).(b,a ),(b,b ),(c,c),( d,d), (d,e).(e,d ),(e,e )}
用h s a r e t o,造英语单词答:7 letter word(s):EARSHOT.6 letter word(s):AHORSE, ASHORE, EARTHS, HATERS, HEARTS, HOARSE, HORSTE, OATERS, ORATES, OSETRA, OTHERS, RESHOT, THROES, TORAHS.5 letter word(s):AROSE, ASTER, EARTH, ETHOS, HAETS, HARES, HARTS, HASTE, HATER, HATES, HEARS, HEART, HEATS, ...