MO640 - Multiple-choice question

Considering C = {abcd, bcdef, afghijk, bcdgh, ghijk}, choose the alternative that contains all twin sets of this collection:

a) abc, gh, ijk.
b) bcd, ef, hij.
c) bcd, gh, ghi.
d) bcd, gh, ijk.
e) None of the above

Original idea by: Victor de Abreu Iizuka

MO640 - Multiple-choice question

Which of PQ-trees below is not equivalent to following PQ-Tree?

A)

B)

C)

D) 

E) NOTA