Associativity of Group Operation

In summary, the conversation discusses an example where the associativity of an operation is shown. The operation is defined as x*y=x+y+1 and the addition of z is used to demonstrate associativity. The conversation also addresses confusion about how the equation x*(y+z+1)=x+(y+z+1)+1 is derived from the original equation. The expert summarizes that the equation is simply applying the rule for the operation and clarifies that the * does not represent normal multiplication.
  • #1
port31
20
0

Homework Statement


Im looking at this example and trying to figure out how they showed it was associative.
They start out with x*y=x+y+1
then they add in z to show it is associative.
x*(y*z)=x*(y+z+1)=x+(y+z+1)+1=x+y+z+2
I don't know how they go from
this x*(y+z+1)=x+(y+z+1)+1
and end up with the equation on the right.
If i solved for x from x*y=x+y+1 and plugged it in I wouldn't get what they got.
Maybe there is some trick that I am missing.
 
Physics news on Phys.org
  • #2
port31 said:

Homework Statement


Im looking at this example and trying to figure out how they showed it was associative.
They start out with x*y=x+y+1
then they add in z to show it is associative.
x*(y*z)=x*(y+z+1)=x+(y+z+1)+1=x+y+z+2
I don't know how they go from this x*(y+z+1)=x+(y+z+1)+1
and end up with the equation on the right.
They're simply applying the rule for *. If the general rule is x'*y'=x'+y'+1, and you have x*(y+z+1) then you can match up x' with x and y' with (y+z+1):
x*(y+z+1) = x'*y' = x'+y'+1 = x+(y+z+1)+1
If i solved for x from x*y=x+y+1
What do you mean you 'solved it'? The * doesn't stand for normal multiplication here. x*y=x+y+1 is defining an operation '*'.
 
  • #3
oh ok i see now, thanks for your help.
 

1. Is associativity important in group theory?

Yes, associativity is a fundamental property in group theory. It allows us to combine three or more elements in a group in any order without changing the result.

2. What does it mean for a group to be associative?

A group is associative if the order in which elements are grouped in an operation does not affect the final result.

3. How can I determine if a group is associative?

To determine if a group is associative, you can perform the associative property test. This involves grouping the elements in different ways and checking if the results are the same. If they are, the group is associative.

4. Are all groups associative?

No, not all groups are associative. Some examples of non-associative structures include non-associative algebras and non-associative rings.

5. What is an example of an associative group?

The set of integers under addition is an example of an associative group. This means that when adding three or more integers, the order in which they are grouped does not affect the final result.

Similar threads

  • Calculus and Beyond Homework Help
Replies
9
Views
1K
  • Calculus and Beyond Homework Help
Replies
3
Views
523
  • Calculus and Beyond Homework Help
Replies
8
Views
475
  • Calculus and Beyond Homework Help
Replies
19
Views
1K
  • Calculus and Beyond Homework Help
Replies
3
Views
564
  • Calculus and Beyond Homework Help
Replies
8
Views
877
  • Calculus and Beyond Homework Help
Replies
4
Views
1K
  • Calculus and Beyond Homework Help
Replies
10
Views
479
  • Calculus and Beyond Homework Help
Replies
2
Views
1K
  • Calculus and Beyond Homework Help
Replies
3
Views
1K
Back
Top