Hello, everyone: My question is about the states of paired electrons in BCS Theory. According to Tinkham's book (pages 70-71), electron states in the superconducting gap (SG) in normal state are push up to above the upper edge of the SG in superconducting state; on the other hand, it seems that electrons on these pushed up states actually have energy lower than the lower edge of SG. Is this understanding correct? How can an electron on a state above SG be said to have an energy lower than SG? An electron on an energy state should have the energy of that state? Thank.