This might be a really stupid question but what is the signifigance of having a something like this /r > Which is supposed to be an r vector inside of a ket. In the book I'm reading they use this notation when talking about the shrodinger equation, where r is the positon vector. I'm sort of confused because at some point a big deal is made of making a distinction between kets/bras and the vectors (arrows) we all know and love. So the arrows are a certain subset of vecotrs in a vector space (R^3), and there's a relation between kets and vectors but I don't understand what it means to have a vector, like the position vector inside as a ket. Maybe I'm just thinking too much and making something out of nothing?