DM-Groups and Lattice-Q10

+1 vote

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Which of the above hasse diagrams (a),(b),(c) is/are is lattice? 

(A).Only (a)

(B).Only (a) and (c)

(C).Only (b) and (c) 

(D).All of (a),(b) and (c)

asked Jul 8 in Discrete Maths by gbeditor (11,310 points)
reshown Jul 9 by gbeditor

2 Answers

0 votes
B is correct one
answered Jul 9 by tsnikhilsharmagate2018 (18,160 points)
+1 vote
for a hasse diagram to be lattice every pair of element must have unique LUB and GLB.

in diagram b

LUB(b,c)= d or e            GLB(d,e)=b,c

so diagram b is not lattice
answered Jul 9 by tscontactadarshkumar (4,600 points)
Yes This type of diagram called cross structure poset
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