Exploration of Ethnomathematics in the Kabihu Kinship System from the Perspective of Set Theory and Relations

This study was motivated by the importance of linking mathematics learning to local cultural contexts so that mathematical concepts become more meaningful. The kabihu kinship system in Sumba society has a social structure that can potentially be interpreted through mathematical concepts, particularly sets and relations. This study aims to explore the structure of the Praikaraha kabihu in Raja Prailiu Village, East Sumba, and to identify the forms of sets and types of relations that can be interpreted mathematically. The study employs a qualitative approach using ethnography. Three informants were selected through purposive sampling based on the following criteria: understanding the history and structure of the kabihu, being involved in traditional life, and being able to provide information regarding kinship relationships within the kabihu. Data were collected through semi-structured interviews, non-participant observation, and documentation. Data analysis was conducted through the stages of ethnographic analysis, which include the identification of cultural domains, the grouping of categories, and the interpretation of cultural meanings, and was supported by Miles and Huberman’s interactive model through data condensation, data presentation, and the drawing and verification of conclusions. Data validity was examined through source triangulation, methodological triangulation, and member checking. The research results indicate that members of the Kabihu Praikaraha can be understood as a set consisting of individuals based on lineage and Kabihu membership. Relationships were found in kinship and marital ties, including those between the Kabihu and related groups such as the Anakawini and Angupaluhu. These findings indicate the existence of a cultural structure that can be interpreted through the concepts of sets and relations. Thus, the Kabihu system has the potential to be used as a context or resource for ethnomathematics-based mathematics learning, particularly in the areas of sets and relations.