History

Time	Change
2009-05-10 11:01:19+00:00	Created
2009-05-10 11:01:19+00:00	Associated with 符号
2009-05-10 11:01:19+00:00	Associated with sign
2009-05-10 11:01:38+00:00	Associated with sign(x)
2009-05-10 11:01:38+00:00	Associated with sign()
2019-06-05 12:29:53+00:00	Associated with 正負の符号