The weight
-sheaf
helps
us to reinterpret Morse–Novikov cohomologies via sheaf theory. We give several
theorems of Künneth and Leray–Hirsch types. As applications, we prove that the
-Lefschetz number
is independent of
and calculate the Morse–Novikov cohomologies of projective bundles. Based on these
results, we give two blow-up formulae on (not necessarily compact) complex
manifolds, where the self-intersection formulae play a key role in establishing the
explicit expressions for them.