  Given one quasi-smooth derived space cut out of another by a section of a
2-term complex of bundles, we give two formulae for its virtual cycle.
  They are modelled on the the $p$-fields construction of Chang-Li and the
Quantum Lefschetz principle, and recover these when applied to moduli spaces of
(stable or quasi-) maps. When the complex is a single bundle we recover results
of Kim-Kresch-Pantev.
