@Opus 17 said "Emancipated child. If a child is emancipated under state law, the child is treated as not living with either parent".
Not exactly. He is treated as not being in the "custody" of either parent. And, that is what makes the special rule (for separated parents) void. Once the child is emancipated, the parents can no longer split the tax benefits and the custodial parent can no longer release the exemption (dependency) to the non custodial parent. If the child physically lives with one of the parents, including temporary absence to attend college, the child is still the QC of that parent (the mother in this case).
