Prove the following statements!
1. If A and B are sets then
(a) |A ∪ B| = |A| + |B| − |A ∩ B| and
(b) |A × B| = |A||B|.
2. If the function f : A→B is
(a) injective then |A| ≤ |B|.
(b) surjective then |A| ≥ |B|.
3. For each part below, there is a function f : R→R that is
(a) injective and surjective.
(b) injective but not surjective.
(c) surjective but not injective.
(d)...
For each of the following sets, prove that thay are convex sets
or not. Also graph the sets.
a) ? 1= {(?1 , ?2 ): ?1 ^2 + ?2^2 ≥ 1}
b)?2 = {(?1 ,?2 ): ?1 ^2 + ?2^ 2 = 1}
c)?3 = {(?1 , ?2 ): ?1 ^2 + ?2 ^2 ≥ 1}
1)Prove that the intersection of an arbitrary collection of
closed sets is closed.
2)Prove that the union of a finite collection of closed sets is
closed
Prove the following statements!
1. Let S = {0, 1, . . . , 23} and define f : Z→S by f(k) = r
when 24|(k−r). If g : S→S is defined by
(a) g(m) = f(7m) then g is injective and
(b) g(m) = f(15m) then g is not injective.
2. Let f : A→B and g : B→C be injective. Then g ◦f : A→C is
injective.
3. Let f : A→B and g : B→C be surjective....
Question 4 Prove that the following language is not regular. ? =
{ 0 ?1 ? | ?, ? ≥ 0, ? ≠ 2? + 1 }
Question 5 Prove that the following language is not regular. ? =
{ ? ∈ { 0, 1, 2} ∗ | #0 (?) + #1 (?) = #2 (?) } where #? (?)
denotes the number of occurrences of symbol a in string w.
Unless otherwise noted, all sets in this module are finite.
Prove the following statements...
1. If A and B are sets then (a) |A ∪ B| = |A| + |B| − |A ∩ B|
and (b) |A × B| = |A||B|.
2. If the function f : A→B is (a) injective then |A| ≤ |B|. (b)
surjective then |A| ≥ |B|.
3. For each part below, there is a function f : R→R that is (a)
injective and surjective. (b)...
Prove that the 0/1 KNAPSACK problem is NP-Hard. (One way to
prove this is to prove the decision version of 0/1 KNAPSACK problem
is NP-Complete. In this problem, we use PARTITION problem as the
source problem.)
(a) Give the decision version of the O/1 KNAPSACK problem, and
name it as DK.
(b) Show that DK is NP-complete (by reducing PARTITION problem
to DK).
(c) Explain why showing DK, the decision version of the O/1
KNAPSACK problem, is NP-Complete is good...