is there an autoregressive model that can have granger causality what is the granger causality why is granger causality important what is granger theory is granger causality true granger causality issue is it necessary to create a stable vector autoregressive granger model? why is the ver model necessary which model is necessary to create a stable vector autoregressive model? what model is granger causality which granger model holds true is granger causality true in a val model or granger model what is granger model is granger model necessary why is it necessary to create granger causality what is the granger causality issues which of the following is a granger causality which model is needed to create a stable vector autoregressive? what is the definition of granger causality what is the role of the granger model?