Actually the notation used in Linear Algebra can be quite different from the notation used in quantum mechanics- though they are both talking about basically the same concept. In Linear Algebra the "inner product" of two vectors, u and v, is represented by <u, v> or sometimes (u, v). In quantum mechanics, what is essentially the "inner product" of two density functions, f and g, is represented by <f | g>. That is normally defined (if I remember correctly) as \(\displaystyle \int f(x)\overline{g}(x) dx\) where "x" is the position variable, the integration is taken over all space, and "\(\displaystyle \overline{g}(x)\)" is the complex conjugate of the function g(x).