Let N and M be compact
3-dimensional manifolds, f : N → M a map. Furthermore let given a Heegaard
splitting for M, which certainly exists if M is closed, and then it is a pair (V,W),
where V , W are handlebodies (possibly non orientable) with M = V ∪ W,
V ∩ W = ∂V = ∂W. It will be shown, that f can be deformed into a normal form
with respect to the Heegaard splitting of M: either f has the absolute degree 0, or f
is homotopic to a map g with the property that g∣g−1(V ) is a covering
map.
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