L ={x^a y^b z^c | c=a+b}
a) Prove that L is not regular.
b)Prove by giving a context-free grammar that the L is context
free.
c)Give a regular expression of the complement L'.
L ={x^a y^b z^c | c=a+b} a) Prove that L is not regular. b)Prove
by giving a context-free grammar that the L is context free. c)Give
a regular expression of the complement L'.
(A) Let a,b,c∈Z. Prove that if gcd(a,b)=1 and a∣bc, then
a∣c.
(B) Let p ≥ 2. Prove that if 2p−1 is prime, then p
must also be prime.
(Abstract Algebra)
Bezout’s Theorem and the Fundamental Theorem of Arithmetic
1. Let a, b, c ∈ Z. Prove that c = ma + nb for some m, n ∈ Z if
and only if gcd(a, b)|c.
2. Prove that if c|ab and gcd(a, c) = 1, then c|b.
3. Prove that for all a, b ∈ Z not both zero, gcd(a, b) = 1 if
and only if a and b have no prime factors in common.
(a) Prove that Q(sqareroot 5)={a+b sqareroot 5 ; a,b in Z} is a
subring of Z.
(b) Show that Q(sqareroot 5) is a conmutative ring.
(c) Show that Q(sqareroot 5) has a multiplicative identity.
(d) show that Q(sqareroot 5) is a field.(Hint : you want to
mulitply something by he conjugate.)
(Abstract Algebra)
Use boolean algebra to prove that:
(A^- *B*C^-) + (A^- *B*C) + (A* B^- *C) + (A*B* C^-) + (A*B*C)=
(A+B)*(B+C)
A^- is same as "not A"
please show steps to getting the left side to equal the right
side, use boolean algebra properties such as distributive,
absorption,etc