I'm working on my individual dissertation in finance. This thesis tests the low-volatility factor on European markets. The core methodology is creating Fama and French portfolios, testing the new low-volatility factor with the Carhart model and a transaction costs analysis with R.
A friend of mine, who is also writing his thesis this semester, uses the same metrology to test the existence of a new momentum factor in the European markets. Therefore, we developed the core R code together. Although our dissertations are completely different, since we both test other factors, we do use the same code. Would you consider this plagiarism and how do I cope with this issue?