Exercise 17.1.5
“For i=1,2, let e_i=u_iv_i” should be replaced by “Let e_1=u_1u_2 and e=v_1v_2″
Prop. 4.9, Ex.4.2.1
Have I missed something – either in book or errata or other posts? But it seems that: Prop. 4.9 is false, as the mission of Ex. 4.2.1 a) can fail when e is in at least one triangle. E.g., let G be K3, e any edge of K3. Then G/e is K2, and t (G/e)=1, so that t(G\e)+t(G/e) =2, whereas t(G)=3.
Incidence matrix of a digraph – Ex. 1.5.6
The incidence matrix of a digraph (as defined in Ex. 1.5.6) gives no information about the ends of a directed loop. Should it be defined for loopless digraphs only?
Exercise 4.2.15d
The notion of “fundamental cycle” is defined later, in Section 4.3.
(Contributed by Frederic Havet.)
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