Extend completeness and continuity beyond bounded-support fuzzy numbers

Extend the completeness and continuity results established for the uniformly bounded-support fuzzy-number space \(\mathbb{E}^1_{[-M,M]}\) to the entire fuzzy-number space \(\mathbb{E}^1\) and to important subclasses of fuzzy numbers with unbounded support.

Background

The paper develops completeness, cocompleteness, Yoneda completeness, and continuity results for fuzzy numbers whose supports lie within a fixed bounded interval [M,M][-M,M]. It also shows that the unrestricted space E1\mathbb{E}^1 lacks several stronger completeness properties, including finite conical cocompleteness, finite conical completeness, tensoredness, and cotensoredness.

The authors explicitly identify extending the theory from bounded-support fuzzy numbers to the full space E1\mathbb{E}^1, as well as to fuzzy numbers with unbounded support, as an unresolved direction. Such an extension would determine whether analogous order-theoretic and enriched-domain structures can be obtained without the bounded-support assumption.

References

Several open problems remain for future investigation. The present work focuses on bounded-support fuzzy numbers; extending the completeness and continuity results to the entire space $\mathbb{E}1$---or to other important subclasses such as fuzzy numbers with unbounded support---would be a natural next step.

A Natural Fuzzy Order on Fuzzy Numbers  (2609.09811 - Kou et al., 9 Sep 2026) in Section 6, Conclusion, item (1)