In the context of unevenly spaced (multiple) time series (USTS), are there any classical approaches? If they were evenly spaced, we would try ARIMA, or VAR, or even State-Space models.
I've been searching for bibliography, and from what I could tell, it seems that this field of USTS hasn't been as well developed as the evenly spaced time series, and it's a bit hard to tell which references are the 'classical' ones in this field.
Also, I'm not necessarily restricting the question to those models more similar to classical one like ARIMA, etc. I'm also interested in Machine Learning (and DL) models that are capable of dealing with USTS.
P.S.: There's this highly voted question on Cross Validated, but it was asked almost 10 years ago. Maybe things have improved since then...
frequency domain approach, for examplespectrum analysis, which help us exploit the traits and whatnot for each frequency (i.e., different intervals). But that might not give you information that you'd expect from atime domain approach. – stucash May 07 '22 at 18:32