S = Z (integers), R = {(a,b) : a = b mod 5}. Is this relation an
equivalence relation on S?
S = Z (integers), R = {(a,b) : a = b mod 3}. Is this relation an
equivalence relation on S? If so, what are the equivalence
classes?
1. Consider the group Zp for a prime p with multiplication
multiplication mod p). Show that (p − 1)2 = 1 (mod p)
2. Is the above true for any number (not necessarily prime)?
3. Show that the equation a 2 − 1 = 0, has only two solutions
mod p.
4. Consider (p − 1)!. Show that (p − 1)! = −1 (mod p) Remark:
Think about what are the values of inverses of 1, 2, . . ....
Let
t= 20389208 mod 4 and M= t+25
a. Find integers a and b such that 0<a<M, 0<b<M
and ab= 0 (mod M)
b. Find integers a and b such that 0<a<M, 0<b<M
and ab= 1 (mod M)
Thank you in advance!
Show that every permutational product of a finite amalgam
am(A,B: H) is finite.Hence show that every finite amalgam of two
groups is embeddable in a finite group.
Let P be the uniform probability on the integers from 1 to 99.
Let B be the subset of numbers which have the digit 3. Let A be the
subset of even numbers. What is P(A), P(B)? What is P(A|B)?
P(B|A)?