1E

Consider the following equations:

The values 5 and 11 are relatively prime to each other.

Apply the Chinese remainder theorem to find the solutions to the equations (1).

Refer chapter 31, section 31.5, theorem 31.27 of textbook for Chinese remainder theorem.

Calculate the values of s and t, such that and .

Use random value substitution method to find the values of s and t.

Choose s = 20 and t = – 9.

So, the s = 20 and t = – 9 values satisfies the equation .

Now, calculate the value of as below:

Then is a special solution of the simultaneous congruence equations and .

Therefore, the general solution is .

2E

Consider x is an integer such that, it leaves 1, 2, and 3 as remainders when divided by 9, 8, and 7 respectively.

x satisfies the following equations:

9 is relatively prime to 8, 8 is relatively prime to 7, and 9 is relatively prime to 7. So, the values 9, 8, and 7 are relatively prime pairs (the pairs are (9,8), (8,7), and (9,7)).

Consider the equations (1) and (2).

Apply the Chinese remainder theorem to find the solutions to the equations (1) and (2) as 9 and 8 are relatively prime.

(Refer chapter 31, section 31.5, theorem 31.27 of textbook for Chinese remainder theorem.)

Calculate the values of s and t, such that and .

Use random value substitution method to find the values of s and t.

Choose s = 1 and t = –1.

So, the values s = 1 and t = –1 satisfies the equation .

Now, calculate the value of as below:

Then, is a special solution of the simultaneous congruence equations and .

Hence, the general solution of these two congruencies (1) and (2) is .


Now, solve the two simultaneous congruencies and equation in (3) using Chinese remainder theorem.

Calculate the values of s and t, such that and .

Use random value substitution method to find the values of s and t.

Choose s = –3 and t = 31.

So, the values s = –3 and t = 31 satisfies the equation .

Now calculate the value of as below:

Then, is a special solution of the simultaneous congruence equations and .

The general solution of these two congruencies is .

Hence, the general solution of the three congruencies in (1), (2), and (3) is


Calculate the value of x using the equation (4).

Then x can be written as follows:

That is

Therefore, the integers of the form leave remainders 1, 2, and 3 when divided by 9, 8, and 7 respectively.

3E

Consider a set,

Here,

Such that are pairwise relatively prime.

Consider,

Consider a one-to-one correspondence mapping define from to.

…… (1)

Here, respectively.

Similarly for the mapping (1) can be define as

Such that


Consider,

Therefore,

As form the finite abelion group with respect to multiplication and thus it can be said that the inverse of say will belong to.

Thus,


Define,

That is

Therefore,

Define,

…… (2)

As therefore with reference to the corollary 31.26 it can say that thus the expression (2) is well define.

Write as a function of as


For

Which implies,

And

Thus,

Here is at the ith position.

Consider,

As

Therefore,

Thus,

Hence, Proved

4E
Chegg Rip, Introduction to Algorithms, 3rd Edition. [RipVer 0.1] (index)