22/01/27 07:40:50.15 fTQ+efrZ.net
>>557
>両側無限列あるいは双方向無限列 (doubly or bi-infinite sequence) である（前記>>556）
英語版にもあるよ
分からない人は
下記
「For example, the sequence (a_{n})_{n=1}^{∞ } is the same as the sequence (a_{n})_{n∈ N }, and does not contain an additional term "at infinity".」
を百回音読してくださいｗ
URLﾘﾝｸ(en.wikipedia.org)
Sequence
The limits ∞ and -∞ are allowed, but they do not represent valid values for the index, only the supremum or infimum of such values, respectively.
For example, the sequence (a_{n})_{n=1}^{∞ } is the same as the sequence (a_{n})_{n∈ N }, and does not contain an additional term "at infinity".
The sequence (a_{n})_{n=-∞ }^{∞ } is a bi-infinite sequence, and can also be written as (・・・ ,a_{-1},a_{0},a_{1},a_{2},・・・ ).