Matrix algebra in high school: Didactic transposition to the regular and the emergency COVID-19 outbreak curriculum

As the impact of the COVID-19 outbreak, Indonesia has regulated the emergency curriculum as an optional solution for schools that have difficulty implementing the regular curriculum. Matrix algebra is one of the topics that remain compulsory regardless of the choice of the curriculum. This topic has shifted from what mathematicians first formulated. This study examines the didactic transposition from scholarly knowledge of matrices to the presentation of matrices in the Indonesian high school curriculum, both the regular and the emergency. We analyzed the scholarly knowledge with literature detailing the history of matrix algebra. Then we explored how matrices were taught in high school mathematics curriculum using curriculum resources and the national textbook. The results showed structural trajectory changes, reductions, and "desynchretization" as scholarly knowledge was transposed to the school curriculum. We also found that the transposition might cause learning obstacles for students to understand matrix algebra.