1
GATE CSE 2001
MCQ (Single Correct Answer)
+2
-0.6
Consider an undirected unweighted graph G. Let a breadth-first traversal of G be done starting from a node r. Let d(r, u) and d(r, v) be the lengths of the shortest paths from r to u and v respectively in G. If u is visited before v during the breadth-first traversal, which of the following statements is correct?
A
d(r, u) < d(r, v)
B
d(r, u) > d(r, v)
C
d(r, u)$$ \le $$d(r, v)
D
None of the above
2
GATE CSE 2001
MCQ (Single Correct Answer)
+2
-0.6
How many undirected graphs (not necessarily connected) can be constructed out of a given set V = { v1,v2,........,vn } of n vertices?
A
$$\frac{n(n-1)} {2}$$
B
2n
C
n!
D
$$2^\frac{n(n-1)} {2}$$
3
GATE CSE 2001
MCQ (Single Correct Answer)
+2
-0.6
Which of the following relational calculus expressions is not safe?
A
$$\left\{t \mid \exists u \in R_1\left(t[A] = u[A]\right) \land \neg \exists s \in R_2 \left(t[A] = s[A]\right)\right\}$$
B
$$\left\{ t \mid \forall u \in R_1\left(u[A]="x"\Rightarrow \exists s \in R_2\left(t[A] = s[A] \land s[A] = u[A]\right)\right) \right\}$$
C
$$\left\{t \mid \neg (t \in R_1)\right\}$$
D
$$\left\{t \mid \exists u \in R_1\left(t[A]=u[A]\right) \land \exists s \in R_2 \left(t[A] = s[A]\right)\right\}$$
4
GATE CSE 2001
MCQ (Single Correct Answer)
+2
-0.6
$$R(A,B,C,D)$$ is a relation. Which of the following does not have a lossless-join, dependency preserving $$BCNF$$ decomposition?
A
$$A \to B,\,B \to CD$$
B
$$A \to B,\,B \to C.\,C \to D$$
C
$$AB \to C,\,C \to AD$$
D
$$A \to BCD$$