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宿儒 星宿 宿舍 着急 着凉 着火 处理 处分 处所 和睦 和面 暖和
σF(R)、πA(R)、R×S EA(R)、VA(S)、R*S R∩S、R∪S、R×S πA(R)、σF(R)、R×S
S-(R-S) R-(R-S) (R-S)∪S R∪(R-S)
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R∪s、R∩S、σF( R∪S、R∩S、πA( R∩S、R∪S、πA( R∩S、R∪S、σF(
S-(R-S) R-(R-S) (R-S)∪S R∪(R-S)
2R,3S,4S,5R 2R,3S,4R,5R 2R,3R,4S,5R 2S,3R,4S,5S 2S,3R,4R,5S
σF(R)、 πA(R)、R×S EA(R)、VA(S),R*S R∩S、R∪S、R×S σA(R)、σF(R)、R×S
σF(R),πA(R)、R×S EA(R)、VA(S)、R*S R∩S、R∪S、R×S πA(R),σF(R)、R×S
R-S=R-(R∩S) R=(R-S)∪(R∩S) R∩S=S-(S-R) R∩S=S-(R-S)
R-S=R-(R∩S) R=(R-S)∪(R∩S) R∩S=S-(S-R) R∩S=S-(R-S)
S-(R-S) R-(R-S) (R-S)∪S R∪(R-S)
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宿儒(sù) 锡箔(bó)秕谷(bǐ) 收敛(liǎn) 菜畦(wā) 狗窦(dòu)觅食(mì) 珊瑚(shān) 盔甲(kuēi) 斑蝥(máo)渊博(yuān) 缠络(chán) 竹筛(shāi) 鼎沸(dǐng)绣像(xiòu) 蟋蟀(shuài)
R-S=R-(R∩S) R=(R-S)∪(R∩S) R∩S=S-(S-R) R∩S=S-(R-S)
(R-S)-S S-(S-R) (S-R)-R S-(R-S)