Symmetries and fluctuations in the nuclear density functional

We first discuss basic questions, such as confining the center of mass and taking advantage of the rotation invariance of the Hamiltonian, but also the quest for universality with respect to proton and neutron numbers. Our second subject is the need, in calculations of energy surfaces, to remember that collective coordinates are quantum operators B. This allows fluctuations Δb possibly degrading the quality of that label used as an argument for the energy function e(b).