##
**Analytical expressions for the addition of fuzzy intervals.**
*(English)*
Zbl 0919.04005

Summary: The addition of fuzzy quantities is undeniably the most important operation in fuzzy arithmetic. In this paper, we consider the general case of the addition of fuzzy intervals based on a continuous triangular norm. We start our discussion with an extensive literature review in which we recall explicit formulae for the addition based on the strongest and the weakest triangular norm, for the addition based on the algebraic product, and several recent results for the addition based on a continuous Archimedean triangular norm, including specific theorems for strict and nilpotent triangular norms. Subsequently, the addition based on an ordinal sum is studied, and it is shown how this addition can be transformed into a series of additions based on the summands of this ordinal sum. This important observation implies that the addition based on an arbitrary continuous triangular norm can be practically performed, provided the summands of the corresponding ordinal sum representation and the fuzzy intervals involved fulfil the appropriate conditions mentioned in the overview. This is illustrated by means of several examples.

### MSC:

03E72 | Theory of fuzzy sets, etc. |

### Keywords:

t-norm; addition; fuzzy quantities; fuzzy arithmetic; fuzzy intervals; triangular norm; ordinal sum
PDF
BibTeX
XML
Cite

\textit{B. De Baets} and \textit{A. Marková-Stupňanová}, Fuzzy Sets Syst. 91, No. 2, 203--213 (1997; Zbl 0919.04005)

Full Text:
DOI

### References:

[1] | De Baets, B.; Marková, A., Addition of LR-fuzzy intervals based on a continuous \(t\)-norm, (Proc. 6th Internat. Conf. on Information Processing and Management of Uncertainty in Knowledge-Based Systems, vol. I (1996)), 353-358, Granada, Spain |

[2] | Dubois, D.; Prade, H., Additions of interactive fuzzy numbers, IEEE Trans. Automat. Control, 26, 926-936 (1981) · Zbl 1457.68262 |

[3] | Dubois, D.; Prade, H., Fuzzy numbers: an overview, (Bezdek, J., Analysis of Fuzzy Information, vol. 2 (1988), CRC Press: CRC Press Boca Raton), 3-39 |

[4] | Fullér, R.; Keresztfalvi, T., \(T\)-norm-based addition of fuzzy intervals, Fuzzy Sets and Systems, 51, 155-159 (1992) |

[5] | Hong, D., A note on the product-sum of \(L-R\) fuzzy numbers, Fuzzy Sets and Systems, 66, 381-382 (1994) · Zbl 0844.04005 |

[6] | Hong, D.; Hwang, S., On the compositional rule of inference under triangular norms, Fuzzy Sets and Systems, 66, 25-38 (1994) · Zbl 1018.03511 |

[8] | Kolesárová, A., Triangular norm-based additions of fuzzy numbers and preserving of similarity, BUSEFAL, 69, 43-54 (1997) |

[9] | Ling, C., Representation of associative functions, Publ. Math. Debrecen, 12, 189-212 (1965) · Zbl 0137.26401 |

[10] | Mareš, M., Computation over Fuzzy Quantities (1994), CRC Press: CRC Press Boca Raton · Zbl 0859.94035 |

[11] | Marková, A., Additions of \(L-R\) fuzzy numbers, BUSEFAL, 63, 25-29 (1995) |

[12] | Marková, A., \(T\)-sum of \(L-R\) fuzzy numbers, Fuzzy Sets and Systems, 85, 379-384 (1997) · Zbl 0904.04007 |

[13] | Marková-Stupňanová, A., A note to the addition of fuzzy numbers based on a continuous Archimedean t-norm, Fuzzy Sets and Systems, 91, 251-256 (1997) · Zbl 0919.04010 |

[14] | Mesiar, R., Computation over LR-fuzzy numbers, (Proc. 5th Internat. Workshop on Current Issues in Fuzzy Technologies. Proc. 5th Internat. Workshop on Current Issues in Fuzzy Technologies, Trento, Italy (1995)), 165-176 |

[15] | Mesiar, R., A note to the \(T\)-sum of \(L-R\) fuzzy numbers, Fuzzy Sets and Systems, 79, 259-261 (1996) · Zbl 0871.04010 |

[16] | Mesiar, R., Shape preserving additions of fuzzy intervals, Fuzzy Sets and Systems, 86, 73-78 (1997) · Zbl 0921.04002 |

[17] | Schweizer, B.; Sklar, A., Probabilistic Metric Spaces (1983), North-Holland: North-Holland New York · Zbl 0546.60010 |

[18] | Triesch, E., On the convergence of product-sum series of \(L-R\) fuzzy numbers, Fuzzy Sets and Systems, 53, 189-192 (1993) · Zbl 0874.26019 |

This reference list is based on information provided by the publisher or from digital mathematics libraries. Its items are heuristically matched to zbMATH identifiers and may contain data conversion errors. It attempts to reflect the references listed in the original paper as accurately as possible without claiming the completeness or perfect precision of the matching.