SLAM stands for "simultaneous location and mapping", it's about being in an unknown environment which you need to both map and localise yourself in. I'm familia

SLAM stands for "simultaneous location and mapping", it's about being in an unknown environment which you need to both map and localise yourself in. I'm familiar with it in the context of robotic navigation, but it seems Hololens deals with it too - mapping the environment to place holograms, localising within that environment because you need to be able to interact with them. Most smartphones simply don't have to do this, they don't have to map their environments without user input. They don't have to localise themselves within a map of the environment that they've built themselves. Project Tango does do AR and environment mapping on a smartphone, so it does deal with the SLAM problem too.