Demir, İzzettin2021-12-012021-12-0120210170-42141099-1476https://doi.org/10.1002/mma.7266https://hdl.handle.net/20.500.12684/10086Fatimah et al. suggested different complement operations for N-soft sets. However, these operations do not comply with De Morgan's laws and double complementation law for N-soft sets. So we do not restate some classical theorems on topological spaces in the realm of N-soft sets. Besides, the mappings are a basic mathematical tool which is utilized in numerous areas of mathematics, other sciences, and their applications. But there is not any note on the mappings in the setting of N-soft set theory. To deal with these problems, firstly, we advance the concept of complement of an N-soft set and demonstrate that De Morgan's laws and double complementation law are satisfied in N-soft set theory according to this new definition. Then we present an idea of the N-soft mappings and investigate some of their properties. Also, we illustrate given properties with examples and counter examples. Finally, using the N-soft mappings, we describe a mathematical system design for diagnosing purpose of the Covid-19 disease.en10.1002/mma.7266info:eu-repo/semantics/closedAccessdecision makingN&#8208soft mappingN&#8208soft setrelative complementsoft setArticle448734373582-s2.0-85100489978WOS:000614754100001Q1Q1