\(\Large\textbf{蠢疯是不识}\{n+1,n+2,n+3,\ldots\}\textbf{的集论白痴}\)

elim

蠢疯说：由于\(\displaystyle\bigcup_{m=1}^\infty A_m^c =\big(\bigcap_{m=1}^\infty A_m\big)^c\)
所以当且仅当\(\displaystyle\big(\bigcap_{m=1}^\infty A_m\big)^c=\varnothing\)时\(\displaystyle\bigcup_{m=1}^\infty A_m^c=\mathbb{N}\)
而德摩根定律说当且仅当\(\displaystyle\bigcap_{m=1}^\infty A_m=\varnothing\)时\(\displaystyle\bigcup_{m=1}^\infty A_m^c=\mathbb{N}\)
蠢疯跟德摩根对着干不是故意的，只是种太孬。