Is {R-Z} a Subring of the Reals?

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In summary, the conversation discusses whether the set S = {R-Z}, the set of all reals that are not integers, is a subring of R. It is determined that S is not a subring because it is not closed under subtraction. The speaker believes they are right and mentions that some students in their class do not believe 0 is an integer and think two distinct elements must be chosen to show it's not closed.
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1800bigk
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Let S = {R-Z}, the set of all reals that are not integers. Is S a subring of R? I think not because 1/2 is in S but 1/2-1/2=0 so S is not closed under subtraction so is not a subring.

is that right?
 
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  • #2
what do you think? and why do you think it? if i say you are wrong, would you believe me? why or why not?
 
  • #3
i think I am right, I am asking because some of the kids in my class said zero is not an integer and they said i should of picked two distinct elements to show its not closed but i said it didnt matter.
 
  • #4
In which class are you learning about rings where the students don't believe that 0 is an integer and believe that you have to pick two distinct elements to show it's not closed?
 

FAQ: Is {R-Z} a Subring of the Reals?

What is a subring?

A subring is a subset of a ring that is also a ring itself. It contains the same operations (addition and multiplication) and follows the same rules as the larger ring.

How can I determine if S is a subring of R?

To determine if S is a subring of R, you need to check if S satisfies the three subring conditions: closure under addition and multiplication, contains the identity element, and contains the additive and multiplicative inverses of each element.

What does it mean for S to be a proper subring of R?

If S is a proper subring of R, it means that S is a subring of R, but not equal to R. This means that S contains a subset of the elements in R and follows the same operations and rules, but is not the same as R.

Can a subring have a different identity element than the larger ring?

No, a subring must have the same identity element as the larger ring. This is one of the three subring conditions that must be satisfied in order for S to be a subring of R.

How is a subring different from a subgroup?

A subring is a subset of a ring that is also a ring, while a subgroup is a subset of a group that is also a group. While both subrings and subgroups follow the same operations and rules as the larger structure, they differ in the type of structure they belong to (ring vs. group).

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