3. Weakly S- Prime Hyperideals
In this section the fundamental properties of weakly S− prime hyperideals are studied.
Definition 3.1. Let be a multiplicative hyperring, be a multiplicative closed subset of and be a proper hyperideal of such that .
A proper hyperideal is said to be a weakly S− prime hyperideal then there exists an such that if whenever then for all then either or .
Example 3.2.
Let us define the hyperoperation on the ring of integers as for all ;. Let us give be a closed multiplicative subset of and be hyperideal of such that We will show that is a weakly S− prime hyperideal of .
Let and there exists such that . Let’s find out .
Therefore; , and hence is a weakly S− prime hyperideal of .
Now we will show weakly prime hyperideals and the relationship between S− prime hyperideals and weakly S− prime hyperideals.
Proposition 3.3 Suppose that is a multiplicative hyperring, is multiplicative closed subset of which is include and is a proper hyperideal of such that . In this case every weakly prime hyperideal of is a weakly S− prime hyperideal.
Proof: Let be a weakly prime hyperideal of . For if then or . If we take then we get either or . Therefore is a weakly S− prime hyperideal of .
Now, let’s give an example of how the converse of a proposition is usually not true.
Example 3.4. Suppose that is a ring for a commutative with identitiy multiplicative hyperring with absorbing elements such that for every subset of the , let’s define the hypermultiplication as for every .
Now, let be a polynomial multiplicative hyperring and let us define the ″″ operation and ″″ hyperoperation for all and as and respectively. Suppose that is a set and is a multiplicative hyperring. Let be a multiplicative polynomial hyperring and be closed multiplicative subset of T and when we take with
Although is a weakly S− prime hyperideal of T, it is not a weakly prime hyperideal for . Because but and .
Proposition 3.5. Suppose that is a multiplicative hyperring, is a multiplicative closed subset of and is a proper hyperideal of such that . In this case every S− prime hyperideal is a weakly S− prime hyperideal.
Proof: Let be a S− prime hyperideal of for and let we take . Since is a S− prime hyperideal of then there exists such that or .
Therefore is a weakly S− prime hyperideal of .
Let us give an example to show that the converse of the above statement is generally not true.
Example 3.6. Let be the hyperoperation defined on the multiplicative hyperring for every . Let be a multiplicative closed subset of and
be a hyperideal of such that . Eventhough is a weakly S− prime hyperideal of , it is not a S− prime hyperideal of . Because for , but and .
Lemma 3.7. Suppose that is a multiplicative hyperring, is a multiplicative closed subset of , and are two hyperideals of such that and . If and are two S− prime hyperideals of then is a S− prime hyperideal of .
Lemma 3.8. Let be a multiplicative hyperring, be a multiplicative subset of , and be two hyperideals of such that and . If I and J be two weakly S− prime hyperideals of then be a weakly S− prime hyperideal of .
Proof: Since every S− prime hyperideal is a weakly S− prime hyperideal so is a weakly S− prime hyperideal of .
In the following proposition, we will prove that the hyperproduct of two weakly S− prime hyperideals is also a weakly S− prime hyperideal.
Proposition 3.9. Suppose that is a multiplicative hyperring, is a multiplicative closed subset of , and are two hyperideals of such that and . If and are weakly S− prime hyperideals of then is a weakly S− prime hyperideal of .
Proof: Let
for all
and
. Because
and
are weakly
S− prime hyperideals of
there exists
such that
or
and
or
and
is a hyperideal of
by [
7]. Therefore we get
for
. According to Lemma
the intersection two weakly
S− prime hyperideals is also weakly
S− prime hyperideal and since
we get either
or
. Therefore
is a weakly
S− prime hyperideal of
.
Proposition 3.10. Let be a multiplicative hyperring be a multiplicative closed subset of and be a hyperideal of such that . If is a weakly S− prime hyperideal of then is a weakly S− prime hyperideal of .
Proof: According to Proposition , is a weakly S− prime hyperideal of .
We proved in Proposition that every S− prime hyperideal is a weakly S− prime hyperideal, and we showed in Example that the converse is generally not true. In the following proposition, we will prove under what conditions the converse is true.
Proposition 3.11. Suppose that is a multiplicative hyperring, is a multiplicative closed subset of and is a weakly S− prime hyperideal of such that and if and only if is a S− prime hyperideal of .
Proof:
If is a weakly S− prime hyperideal of then by assumption for , if then there exists such that or . Let . We will show that a weakly S− prime hyperideal is an S− prime hyperideal. Suppose that for . Let us consider the case where . If then there exists such that .
In this case gives or . If then . Because and is a hyperideal of , that is, if and , then we find . Hence, we get . For an arbitrary and , we find and . Since is hyperideal of , . Therefore .
Similarly; if then there exists such that . Therefore we get either or . If then . Because and is a hyperideal of so we have and is obtained using similar steps to those described above.
Finally; let we consider and . Since there exists such that In this situation; there exists an such that if then or .
Therefore, either or is used to obtain the desired result.
Clear.
The converse of the proposition is generally not true, meaning that a hyperideal with does not necessarily have to be a weakly S− prime.
Example 3.12. Let we define the hyperoperation on the multiplicative hyperring for each , is a multiplicative closed subset of and is a hyperideal of such that . Although , is not S− prime hyperideal of . Because while and are not for . Therefore it is not weakly S− prime.
Corollary 3.13. Suppose that is a multiplicative hyperring, is a multiplicative closed subset and is a is a S− prime hyperideal of such that . Let and is a prime hyperideal of .
Therefore;
is a prime
is a
S− prime by [
9]
is a weakly
S− prime for
.
Proposition 3.14. Assume that is a multiplicative hyperring and is a multiplicative closed subset. Then the following statements are held.
(i) Let be two multiplicative closed subsets of . If be a weakly − prime hyperideal and then be a weakly − prime hyperideal of .
(ii) If S comprise of units of then a proper hyperideal of is weakly prime if and only if is a weakly S− prime.
Proof:
(i) Since and for if then there exists such that or and hence is a weakly − prime hyperideal of .
(ii)
: Let be a weakly S− prime hyperideal of so we have if then there exists such that or for . Since S consist of units of for we get either or . Hence is a weakly prime.
Every weakly prime hyperideal is a weakly S− prime hyperideal.
In Proposition , we proved under what conditions a weakly S− prime hyperideal is a weakly prime hyperideal. Now, let us prove the general condition for this in the following proposition.
Proposition 3.15. Let be a multiplicative hyperring, be a multiplicative closed subset of composed of the units of and be proper hyperideals of with for all . is a weakly prime hyperideal.
Let be weakly S− prime hyperideal of for all . If then there exists with or for and for Because S be consits of the units of we get or .
Every weakly prime hyperideal is a weakly S− prime hyperideal.
Ghiasvand and Farzalipour proved that a necessary and sufficient condition for
to be a prime hyperideal is that
must be an
S− prime hyperideal. [
9] Now we will generalize this to weakly
S− prime hyperideals.
Proposition 3.16. Suppose that is a multiplicative hyperring, is a multiplicative closed subset of and is a proper hyperideal of such that . A proper hyperideal is a weakly S− prime hyperideal if and only if is a weakly prime hyperideal of for some .
Proof:
Let be a weakly S− prime hyperideal of . We have if then there exists such that or . Consider so we get . Let for any so we have . Because is a weakly S− prime hyperideal of there exists we get either or . If then . As for we get and hence we get either or . Since is a weakly S− prime hyperideal then .
Therefore; we get either or leads to or .
Suppose that is a weakly prime hyperideal of . Let for . Because is a hyperideal of so we have and Since is a weakly prime hyperideal thus or . Hence is a weakly S− prime hyperideal of .
Example 3.17. In Example , we showed that is a weakly S− prime hyperideal of the multiplicative hyperring . Now, using this Example , let us show that is a weakly prime hyperideal of . Let and . We will show that . If then . We know is a weakly S− prime hyperideal of so we have . Therefore, we get and hence is a weakly prime hyperideal of . Conversely, if is weakly prime, then it is clear that is weakly S− prime.
Proposition 3.18. Let be a multiplicative hyperring, be a multiplicatice closed subset of R and be a hyperideal of such that . Then
(i) If is a hyperideal of such that and is a weakly S− prime hyperideal of R then is a weakly S− prime hyperideal of .
(ii) Let be a extension of . If is a weakly S− prime hyperideal of then is a weakly S− prime.
Proof:
(i) Let . Let where . Therefore Because so there is . Thus or where is a weakly S− prime hyperideal of .
(ii) Let for . Since is a weakly S− prime of there exists such that or so we get either or . Thus, is a weakly S− prime hyperideal of .
Theorem 3.19. Assume that is a multiplicative hyperring, is a multiplicative closed subset of and let be a good homomorphism such that does not contain zero. If be a weakly- prime hyperideal of then be a weakly S− prime hyperideal of .
Proof: Let where .
We get;
.
Because is a weakly − prime hyperideal there exists such that if then or .
We find, there exists such that or . Thus is a weakly S−prime hyperideal.
Theorem 3.20. Suppose that is a good epimorphism between two multiplicative hyperrings and is a map from to . If is a weakly S− prime hyperideal of and then is a weakly − prime hyperideal of .
Proof: Let for . Since is a good epimorphism there exists such that and . Therefore we get . For and we find .
According to our assumption; is a weakly S− prime hyperideal of so if then there exists with or .
Finally; we find if then there exists with or . Thus, the desired is achieved.
Proposition 3.21. Assume that is a multiplicative hyperring, is a multiplicative closed subset of ; is a hyperideal with . Let be proper hyperideal of that includes I such that . is a weakly S− prime hyperideal of if and only if is a weakly − hyperideal of quotient multiplicative hyperring.
Proof:
Suppose that is a weakly S− prime hyperring of . For if then there exists with or Now let as if then there exists either or . We find there exists either or . Thus, is a weakly − prime hyperideal of .
According to our acceptance; is a weakly S− prime of and hence . Let for . If then there exists either or Thus we find there exists with or . That is, is a weakly S− prime hyperideal of .
Example 3.22. From Example , we know that is a weakly S− prime hyperideal of . Let we use this Example and let for hyperideals and hyperideals of T. then but .
Now, let us prove that the example we gave is generally true.
Theorem 3.23. Let be a multiplicative hyperring be multiplicative closed subset of and be a hyperideal of with . is a weakly S− prime hyperideal of if and only if for each hyperideals of if then there exists either or .
Proof:
Let be a weakly S− prime hyperideal of so we have there exists an such that for with , then or . Now, for and be two hyperideals of . Let for all , both and . Therefore for ; while ; and where . We deduce that is a weakly S− prime hyperideal , which is a contradiction.
For
let
We have
for
,
by [
7] .
According to hypothesis since such that or so we get either or is obtained and desired result is achieved.
Corollary 3.24. Suppose that is a multiplicative hyperring , is a multiplicative closed subset of and is a hyperideal of with is a weakly S− prime hyperideal of if only if for some and for all are hyperideals of if then there exists such that .
Proof:
Let be a weakly S− prime hyperideal of Now let we apply the inductive theorem for . Let us assume our claim is true for and
let for hyperideals for . We have then there exists with . If then or and if ; then there exists such that . In this situation, or but for some must be .
Let for and . We have if . Thus we find there exists an with or for . Therefore is a weakly S− prime hyperideal of .
Proposition 3.25. Let be a multiplicative hyperring, be a multiplicative closed subset of and be a hyperideal of with . be a weakly S− prime hyperideal of if and only if then there exists such that for some and .
Proof:
Let be a weakly S− prime hyperideal of . Let for some and . If then there exists with or or… or . Therefore we get for some .
Let for and for . Since such that or . Hence is a weakly S− prime hyperideal of .
Corollary 3.26. Suppose that is a multiplicative hyperring, is a multiplicative closed subset of and is a hyperideal of such that . Then is a weakly prime hyperideal of if and only if for all hyperideals of , if then for some .
Proof: Take in Corollary .
According to Definition , we know that the intersection of the prime hyperideals of containing the hyperideal of of the multiplicative hyperring is called the prime radical of , and if is a C− hyperideal of , then for some . Therefore, if is a C− hyperideal of the multiplicative hyperring , we will show in the following proposition and theorem, respectively, the property satisfied by Proposition for the set and the property obtained in Proposition for many C− hyperideals of .
Proposition 3.27. Assume that is a multiplicative hyperring, is a multiplicative closed subset of , is a hyperideal of such that . If is a weakly S− prime hyperideal of and is a C− hyperideal of with then there exists such that .
Proof: Let . As is a C− hyperideal of so We get and if then there exists such that and hence Therefore .
Theorem 3.28. Suppose that is multiplicative hyperring, is a multiplicative closed subset of , is a hyperideal of and are weakly S− prime C− hyperideals of such that thus there exists an such that for .
Proof: Let
be weakly
S− prime hyperideals of
for all
and let
. If
are weakly
S− prime hyperideals then
are weakly prime hyperideal for
. If
by[
7],there exists
such that
and hence
.
Theorem 3.29. Let be a multiplicative hyperring and let and respectively be multiplicative closed subsets of each other and . Let and be proper hyperideals of and , respectively. The following statements are equivalent.
(i) be a weakly S− prime hyperideal of .
(ii) be a weakly S− of weakly S− prime hyperideal of and or be a weakly S− prime hyperideal of and .
(iii) be a S− prime hyperideal.
Proof:
Let be a weakly S− prime hyperideal of . Let for and Then there exists either or , we have and . Now let as so We will show that be a weakly S− prime hyperideal of . Let for . Since . We find for thus there exists either or . Since either or then is a weakly − prime hyperideal of . Similarly, if then is a weakly − prime hyperideal of .
Let be a weakly − prime hyperideal of and . Let for and . If then there exists such that or and if then we get .
Consequently; is a − prime hyperideal of . Similarly, if then is a − prime hyperideal of .
Every S− prime hyperideal is a weakly S− prime hyperideal.
Theorem 3.30. Let be a multiplicative hyperring and for . Let respectively be a multiplicative closed subset of for each and be a proper hyperideal of . The following statements are equivalent.
be a weakly S− prime hyperideal of .
For all , and be − prime hyperideal of for some .
be an S− prime hyperideal of .
Proof:
Suppose that is a weakly S− prime hyperideal of . We will continue by induction on m. Let , and be true for . Thus is a weakly − prime hyperideal of . We have is an − prime hyperideal of with or is an − prime hyperideal of such that . If and be − prime hyperideal of , then the proof is complete. Let and weakly S− prime hyperideal of to . If we apply induction theorem for then is − prime hyperideal of for some and for .
Let we apply induction theorem for m. Let we assume our claim is true for and let , and If , and then is − prime hyperideal of and or if is a − prime hyperideal of then . If be − prime hyperideal of and , then the proof is complete. Now suppose that and is an − prime hyperideal of , and let us apply the induction theorem for . Therefore be − prime hyperideal of for some and . Conversely, assume that is a − prime hyperideal of for and for all , . If then be S− prime hyperideal of .
Every S− prime hyperideal is a weakly S− prime hyperideal.
Proposition 3.31. Suppose that is a multiplicative hyperring, is a multiplicative closed subset of and if is a weakly S− prime hyperideal of such that then is a weakly prime hyperideal of .
Proof: Since we have . Let for and for . If then there exists such that for some and . Because we get . Therefore or then we get or and hence or as required.
Proposition 3.32. Assume that is a multiplicative hyperring, are multiplicative closed subsets of and is a weakly T− prime hyperideal of with and . If is a weakly T− prime hyperideal of then is an − prime hyperideal of .
Proof: If
T is a multiplicative closed subset of
then
is a multiplicative closed subset of
by [
10]. Therefore
we have
. Let
for
and
. Therefore there exists
with
. According to our hypothesis, there exists
either
or
thus we find
or
Hence
is a
− prime hyperideal of
.
Let us define the concept of a saturated multiplicative set, as defined in classical algebra, for the localization of multiplicative closed hyperrings.
Definition 3.33. Let be a multiplicative hyperring and be a multiplicative closed subset of . A set S is called a saturated multiplicative closed subset if then both and for all .
Example 3.34. Let be a commutative ring with identity 1. Let us define a hyperoperation . Then is a commutative with identity multiplicative ring. Let such that and let . Then S is a saturated multiplicative closed subset of .
Suppose that S is a multiplicative closed subset of , which is is unit, denotes the saturation of S. Also, is a multiplicative closed subset containing S. A multiplicative closed subset S of is called saturated if . Hence is always a saturated multiplicative closed subset of .
Proposition 3.35. Let be a multiplicative hyperring , be a multiplicative closed subset of and be a hyperideal of which is . is a weakly S− prime hyperideal of if and only if is a weakly − prime hyperideal.
Proof: Since is a saturation of S such that we have If then there exists such that . Let we get and there exists which is where and . If we take we get and let we find . Hence is a weakly − prime hyperideal of .
The following proposition and theorem will characterize weakly S− prime hyperideals.
Proposition 3.36. Assume that is a multiplicative hyperring containing regular elements, is a multiplicative closed subset of and is a hyperideal of such that . The following statements are equivalent.
is a weakly S− prime hyperideal of .
is a weakly prime hyperideal of .
Let be weakly prime hyperideal of and for all there exists such that .
be a weakly prime hyperideal of and for some .
Proof:
is a weakly S− prime hyperideal if and only if is a weakly prime hyperideal of thus by Proposition .
If is a weakly S− prime hyperideal of then is a weakly prime hyperideal of . Let which is associated with and assume that for then we have . Since is a weakly S− prime hyperideal of then there exists either or . Also, since we get , that is . Hence .
We may assume where . Therefore we have either or with . If then there exists and such that thus so we get .
Similarly, it is obtained for , thus the desired result is achieved.
Let where so if then there exists either or . If then there exists or such that . Therefore we find and . According to our assumption then . Similarly it is obtained for . Hence is a weakly S− prime of .
Theorem 3.37. Suppose that is a multiplicative hyperring is a multiplicative closed subset of and is a hyperideal of such that . Then the following assertions are equivalent.
is a weakly S− prime hyperideal of .
There exists such that or for each
There is an , such that if then or for each two hyperideals of .
Proof:
Since is a weakly S− prime hyperideal of , there exists an such that if then for . Let and We will show that . Since there exists with . Since we have . Now, let . We have If then so we get . Suppose that . We have Since is a weakly S− prime hyperideal then we have . Hence so we have . Consequently .
Let and for . Thus . We have and . We will show that . If then . We get . Therefore is a weakly S− prime hyperideal of .
Assume that and are two hyperideals of then . There is an exists an either or for all so we get and Now let show that . Consider such that for . Because so we get . Hence .