local network with Yun

I dont have any expirience on networks so i just want to make a simple question. Is it possible to connect my yun with a mobile device wiressly for data exchange between them without an internet connection?

Yes.

One of the devices will need to act as a WiFi hotspot, probably the Yun as that is it's default operating mode. Then the mobile device connects to the Yun's wireless network. At that point, the two are connected, and can communicate in the same manner as if they were both connected to your home network.