MEASURE:
The maximum degree of the spanning graph.
Good News:
Approximable with an absolute error guarantee of 1 [178].
Bad News:
Not approximable within 3/2
for any
[182].
Comment:
APX-intermediate unless the polynomial-hierarchy collapses
[125].
The generalization of the problem to Steiner trees is also
approximable with an absolute error guarantee of 1 [178].