3.1. Ranking of Nonnegative Normal Neutrosophic Number
Liu and Li (2017) [
6] introduced the concept of the score function
and
, and the accuracy function
and
, as shown in Definition 6. We found some deficiencies with the ranking of these functions, as shown below.
Let be any two NNNs. When , , , , and :
- (1)
If or , then ranking results may be completely opposite;
- (2)
When can determine the ranking result of , the influence of is not considered;
- (3)
Neither the score function nor the accuracy function satisfy the monotonicity.
We use the following example to illustrate problems (1) and (3) mentioned above.
Example 1. Let and be two NNNs, where the specific values are as shown in Table 1. According towe can get its score function and accuracy function from Table 1. For number 1,by , we have . For number 2,by , we have for the numerical results, which are shown in Table 2. From Table 2, when , , , , and are satisfied, we can intuitively see that the score function and accuracy function will be ranked differently if different values are taken. For example, the number 1 satisfies 0.5 < 0.6, 0.2 > 0.1, 0.2 > 0.1, 1 < 2, 0.3 > 0.1; the number 2 satisfies 0.5 < 0.6, 0.2 > 0.1, 0.2 > 0.1, −1 < −0.95, 0.2 > 0.1. However, their ranking results are completely different. The ranking results of numbers 2, 4, 6, 8 in Table 2 are counterintuitive. For example, the number 2 satisfies 0.5 < 0.6, 0.2 > 0.1, 0.2 > 0.1, −1 < −0.95, 0.2 > 0.1, and the ranking result are . However, intuitively, should be ranked first. In order to avoid the disadvantages of the ranking, we propose the nonnegative normal neutrosophic number (NNNN). Additionally, we take into account and introduce the score function and accuracy function of the NNNN.
Definition 9. is an NNNN if it has satisfied Definition 4 and .
Based on the NNNN, the new score function S and accuracy function H are proposed.
Definition 10. Suppose is an NNNN, then its score function isand its accuracy function is According to the score function and accuracy function, the following propositions are derived.
Proposition 1. Let be any two NNNNs, then the following conclusions are obtained.
- (1)
If , , and and , then ;
- (2)
If ,,, and , then
Therefore, we have the following ranking principles.
Definition 11. Let be any two NNNNs, then we have the following method for ranking an NNNN:
- (1)
If , then ;
- (2)
If , then
- (a)
If , then ;
- (b)
If , then .
We introduce some operational laws as follows:
Definition 12. Let be any two NNNNs, then the operational rules are defined as follows:
- (1)
- (2)
Moreover, the relations of the operational laws are given as below, and these properties are obvious.
Proposition 2. Let and be two NNNNs, and ; then
- (1)
- (2)
- (3)
3.2. DGNNNWBM Operator and DGNNNWGBM Operator
This section extends the DGWBM and DGWGBM to NNNN, and proposes the dual generalized nonnegative normal neutrosophic weighted Bonferroni mean (DGNNNWBM) operator and dual generalized nonnegative normal neutrosophic weighted geometric Bonferroni mean (DGNNNWGBM) operator.
Definition 13. Suppose is a set of NNNNs, with their weight vector being , where and . The DGNNNWBM operator is defined aswhere is the parameter vector with . The DGNNNWBM operator can consider the relationship between any elements. Here are some special cases of it.
Remark 1. If , that is, consider the relationship of a single element, then the DGNNNWBM reduces to:which is called a generalized nonnegative normal neutrosophic weighted averaging (GNNNWA) operator. If , that is, consider the relationship between any two elements, then the DGNNNWBM reduces to:which is the nonnegative normal neutrosophic weighted Bonferroni mean(NNNWBM) operator. If , that is, consider the relationship between any three elements, then the DGNNNWBM reduces to:which is called a generalized nonnegative normal neutrosophic weighted Bonferroni mean (GNNNWBM) operator. Theorem 2. Let be a set of NNNNs, then the aggregated result of the DGNNNWBM is also an NNNN andwhere Proof. By Definition 5 and 12, we have
and
so
then
Let
thus
Thereafter
Hence
which completes the proof. ☐
The following example is used to explain the calculation of the DGNNNWBM operator.
Example 2. Let , be two NNNNs. With the weighted vector , and the parameter vector , then, according to Theorem 2, we have
= 0.6327
Similarly, we can obtain
= 0.64
= 0.1265
Similarly, we can obtain
So,
Next, we discuss some properties of the DGNNNWBM operator.
Theorem 3. (Monotonicity) Let and be two sets of NNNNs. If and and and hold for all i, thenwhere is the parameter vector with . Proof. According to the DGNNNWBM operator, we have
By we get .
Let
when
, we can obtain
and
therefore
thus
then
.
Similarly, we can obtain and .
According to Definition 11,
Therefore, the proof is completed. ☐
Remark 2. If , , , and hold for any i, Theorem 3 is still holds.
Theorem 4. (Boundedness) Let be a set of NNNNs. If and , then Proof. By
, according to Theorem 3 and Remark 2, we get
☐
Theorem 5. (Commutativity) Let be a set of NNNNs. If is any permutation of , then Unfortunately, the DGNNNWBM operator is not satisfied with idempotency, i.e., .
Example 3. Let be an NNNN. The weighted vector , and the parameter vector , if all . Similar to Example 2, the following results can be obtained Furthermore, we extend the DGWBGM to NNNNs and propose the dual generalized nonnegative normal neutrosophic weighted geometric Bonferroni mean (DGNNNWGBM) operator.
Definition 14. Suppose is a set of NNNNs with their weight vector being , where and . The DGNNNWGBM operator is defined aswhere is the parameter vector with . The DGNNNWGBM operator can consider the relationship between any elements. Here are some special cases of it.
Remark 3. If , that is, consider the relationship of a single element, then the DGNNNWGBM reduces to:which is called a generalized nonnegative normal neutrosophic weighted geometric averaging (GNNNWGA) operator. If , that is, consider the relationship between any two elements, then the DGNNNWGBM reduces to:which is called a nonnegative normal neutrosophic weighted Bonferroni geometric (NNNWBG) operator. If , that is, consider the relationship between any three elements, then the DGNNNWGBM reduces to: which is called a generalized nonnegative normal neutrosophic weighted Bonferroni geometric (GNNNWBG) operator.
Theorem 6. Let be a set of NNNNs, then the aggregated result of DGNNNWGBM is also an NNNN andwhere The proof of Theorem 6 is similar to that of Theorem 2.
Likewise, an example is used to explain the calculation of the DGNNNWGBM operator.
Example 4. Let , be two NNNNs. The weighted vector , and the parameter vector , then, according to Theorem 6, we have
= 0.6112
Similarly, we can obtain
= 0.5674
= 0.3517
Similarly, we can obtain
So,
The DGNNNWGBM operator has the same properties as the DGNNNWBM operator. The proof is also similar to that of the DGNNNWBM operator. Of particular note, the DGNNNWGBM operator satisfies the property of idempotency.
Theorem 7. (Idempotency) Let be a set of NNNNs. If all , then Proof. Since
, according to operational rules,
Here, is proved by mathematical induction.
When , we have
Suppose , and ,
Then
That completes the proof. ☐
Theorem 8. (Monotonicity) Let and be two sets of NNNNs. If , , , , , and hold for any i, then Theorem 9. (Boundedness) Let be a set of NNNNs. If
and
Theorem 10. (Commutativity) Let be a set of NNNNs. is any permutation of , then