You are hereHome
It would be helpful to make some remarks about the cardinality of J.
If J is finite, then all is good.
However, there are areas where infinite orthonormal bases are common (e.g. Fourier analysis), which leads to difficulties with infinite sums: something has to be said about convergence.
See for example the entry on Fourier coefficients which references this entry.
- Planetary Bugs
- Research Topics
- LaTeX help
- Math Comptetitions
- Math History
- Math Humor
- PlanetMath Comments
- PlanetMath System Updates and News
- PlanetMath help
- Strategic Communications Development
- The Math Pub
- Testing messages (ignore)
- Other useful stuff