Marginal and Complete interactions

Hi,

This may be a very basic question.
If a factor combination is set at a base level in a complete interaction term, why would the whole row and column be at the base level in the marginal interaction term?
Cant the base level of a factor have interaction with another factor with value not at base?

 

"Complete" and "marginal" interactions

A Practitioner's Guide to Generalized Linear Models
A CAS Study Note by Anderson and others.. available at: https://www.casact.org/pubs/dpp/dpp04/04dpp1.pdf may be of some help to understand more about complete and marginal interactions. Particularly from section 2.80 to 2.101. Detailed examples and graphs were provided for reference.

Specific to your question, my understanding is that interactions between the base level factors were considered implicitly while developing the values in the marginal interactions table.