Can I know exact assumption for LASSO and Elastic Net? Since Elastic Net is a hybrid method for LASSO and Ridge Regression, did it have the same assumption as them?
In linear regression, the linear model parameter can be estimated by Ordinary Least Squares (OLS). The estimator can have a bias and a large variance. If the linear model contains many predictor variables or if these variables are correlated, the standard OLS parameter estimates have large variance, thus making the model unreliable.
Regularization is a technique to reduce many predictor variables by penalization of the coefficients, allowing to decrease this variance at the cost of introducing some bias. Ridge regression and LASSO regression are two different penalizations. There are some recommendation, which of them can be preferred in a situation. Elastic net is a convex combination of Ridge and Lasso. They do not imply different assumptions.