A binary search tree is used to locate the number 43. Which of the following probe sequences are not possible?

A library relational database system uses the following schema

USERS (User #, User Name, Home Town)

BOOKS (Books # Book Title, Author Name)

ISSUED (Book #, User #, Date)

Explain in one English sentence, what each of the following relational algebra queries is designed to determine.

(a) $$\sigma_{ \text{User#}=6}\left(\pi_{\text{User#, Book Title}}\left(\left(\text{USERS} \bowtie \text{ISSUED}\right) \bowtie \text{BOOKS}\right)\right)$$

(b) $$\pi_{\text{Author Name}}\left(\text{BOOKS} \bowtie \sigma_{\text{Home Town=Delhi}} \left(\text{USERS} \bowtie \text{ISSUED}\right)\right)$$

Consider the circuit in Fig. Which has a four bit binary number $${b_3}\,{b_2}\,{b_1}\,{b_0}\,$$ as input and a five bit binary number $${d_3}\,{d_2}\,{d_1}\,{d_0}\,$$ as output. The circuit implements:

Consider the circuit in fig shown $$f$$ implements