Lattice


Q1.

Consider the following Hasse diagrams.i.ii.iii.iv.Which all of the above represent a lattice?
GateOverflow

Q2.

Suppose L={p,q,r,s,t} is a lattice represented by the following Hasse diagram: For any x,y\in L not necessarily distinct, x\vee y and x\wedge y are join and meet of x,y respectively. Let L^{3}=\{(x,y,z):x,y,z\in L\} be the set of all ordered triplets of the elements of L. Let P_{r} be the probability that an element (x,y,z)\in L^{3} chosen equiprobably satisfies x\vee (y \wedge z)=(x\vee y)\wedge (x\vee z) . Then
GateOverflow

Q3.

The inclusion of which of the following sets into S = {{1, 2}, {1, 2, 3}, {1, 3, 5}, {1, 2, 4}, {1, 2, 3, 4, 5}} is necessary and sufficient to make S a complete lattice under the partial order defined by set containment?
GateOverflow

Q4.

In the lattice defined by the Hasse diagram given in following figure, how many complements does the element 'e' have?
GateOverflow

Q5.

Consider the set X={a, b,c,d,e} under the partial ordering R={(a,a),(a,b),(a,c),(a,d),(a,e),(b,b),(b,c),(b,e),(c,c),(c,e),(d,d),(d,e),(e,e)}. The Hasse diagram of the partial order (X, R) is shown below. The minimum number of ordered pairs that need to be added to R to make (X, R) a lattice is _____.
GateOverflow

Q6.

The following is the Hasse diagram of the poset [{a,b,c,d,e}, \prec ] The poset is:
GateOverflow