how to implementation latent semantic indexing in python..

[Tim Churches]

Alex Martelli wrote:
> Tim Churches <tchur at optushome.com.au> wrote:
> 
>> malkarouri wrote:
>>> On 13 Jul, 17:18, 78ncp <santi_a... at yahoo.com> wrote:
>>>> hi...
>>>> how to implementation algorithm latent semantic indexing in python
>>>> programming...??
>>> Of course you are aware that LSA is patented..
>> There is a US patent on it, sealed in 1989, but is it patented in any
>> other countries? There is no such thing as a "global patent" - patents
>> only cover the country which issues them. There is a global patent
>> application process (the Patent Co-operation Treaty), but that just
>> establishes a priority date for the invention in each country, but the
>> inventor still needs to file patent applications and have them approved
>> (sealed)  is each and every country. Did Bellcore do that back in the 1980s?
> 
> Aren't patents supposed to last 17 years, anyway?  A patent granted in
> 1989 should have expired in 2006, I believe (though IANAL, so...).

I thought that in the US utility patents (as opposed to plant and
circuit design patents) lasted for 20 years from the filing date, which
was 15th Sept 1988 for the patent in question
(http://www.google.com/patents?vid=USPAT4839853 ). But IANAL either.

Tim C