練習問題 4.2.1

すべての
xs
について真となる等式はどれか,また偽となるのはどれか.


[]:xs = xs
[]:xs = [[],xs]
xs:[] = xs
xs:[] = [xs]
xs:xs = [xs,xs]

常に真なのは

xs:[] = [xs]

上記以外は偽