I am interested in component multisite. I read the manual but my question is still open. Do the component work with only one domain? I won't use more than one domain or subdomains. I want use subfolders. Is that possible? Let me show you what I mean:

Domain structure:
Master: www.mydomain.ltd/
Slave1: www.mydomain.ltd/slave1/
Slave2: www.mydomain.ltd/slave2/
Slave3: www.mydomain.ltd/slave3/
...

Databases on same sql server:
DB_Master: jos_tables
DB_Slave2: jos_tables
DB_Slave3: jos_tables
DB_Slave4: jos_tables
...

Folder structure:
\var\hosts\master\
\var\hosts\slave1\
\var\hosts\slave2\
\var\hosts\slave3\
...

Thanks for advice.

YES as explained in the product detail
www.jms2win.com/download

JMS Multisites is able to parse URL with domain, subdomains and subdirectories.
All the possibilities are availables.

So yes you can decide to have slave site like www.domain.com/slave

In your sample, you have inconsistency between the URL that you mentioned and the directory structure.
If your master (www.domain.tld) is located in directory \var\hosts\master\
then the subdirectories will be located in \var\hosts\master\slaveX
and not beside the master as mentioned.
This will be a subdirectory of your master.