「ill-defined」的意思是「沒有定義描述它是什麼」或者「它只是通過一個不表徵單個對象的句子來解釋」。
我用英語更準確地解釋:
"Ill-defined" means "It does not have definition characterising what it is" or "it is just described by a sentence which does not characterise a single object".
例子:
我定義[1] = 1, [2] = 2^2, [3] = 3^3^3, [4] = 4^4^4^4。我的大數"I WIN數"是[[[[[5]]]]]。所以I WIN數是[[[[[5]]]]] = [[[[5^5^5^5^5]]]] = [[[(5^5^5^5^5)^(5^5^5^5^5)^…^(5^5^5^5^5)]]]] = … >> Rayo數!
它是ill-defined因為[5]没有定義。