^^^Topic^^^
Can I also have a link to proof?
On the same network at the same time, no. Never.
There are IP addresses that are part of the internet world-wide, and are 100% unique. For example, the IP address that your ISP gives on your cable connection. If you connect your computer directly to your cable modem (NO ROUTER in between), then you will be assigned a public IP address. Now let's say you shut down your machine for a week (e.g. you go on vacation). IP addresses that are dynamically assigned are 'recycled'. Since your IP address is not being used, it goes back into the pool to be assigned to somebody else. When you come back from vacation and start up your computer, then it gets assigned another available IP address from the pool. This means that you CAN have multiple IP addresses at different times in this situation, including of course one that has been 'somebody elses' at some previous time. However, you can't have the same IP address as somebody else at the same time.
There is another situation that doesn't apply to what you're asking for, but just so you understand.....
The description ABOVE can be shown like this:
(your computer with public IP address) --> Internet
The description BELOW can be shown like this:
(your computer and others in your house/office with private IP addresss) --> (router with public IP) --> Internet
Notice that the router is in the middle. The router has ONE public IP address (from your ISP), and assigns many "private" IP addresses to devices on the "inside" of your home/office network. These addresses are usually 192.168.x.x, or 10.x.x.x, or 172.x.x.x, and can NEVER be used on the public internet. The router translates the public address on the inside to the one private address visible to the outside. To other computers on the outside it looks like a lot of traffic coming from the one public address. The other computers on the inside of your network are masquerading behind the one public address. So, at home your computer may have an address of 192.168.1.100, and your friend next door (who also has a router) may also have an address of 192.168.1.100, so while you technically have the "same" address as somebody else, that fact is never seen outside of your private home network and his private home network. Publicly, what is seen is your public address, and his public address.