Hello! I asked in this forum about what kind of seasonality the function arima() from stats implements. Now that I have been answered that it implements the Box-Jenkins multiplicative seasonality, I would like to ask whether there is in R possibility to model ARIMA with additive seasonality. I mean whether there is a function or package that implements additive seasonality. In case there is no such function, I would be thankful if someone suggests some code for the purpose. Thank you very much for your attention. Regards, Martin