Z:gnu-www-ja-patent-reform-is-not-enough--9707e2-Under the patent system's rule/en

Under the patent system's rules, whether the public is allowed to use these programs (i.e., whether the patent is invalid) depends on whether there is &ldquo;prior art&rdquo;: whether the basic idea was published before the patent application, which was on June 18, 1990. Williams' publication in April 1991 came after that date, so it does not count.