"Duplicate content" issues
I have 3 levels of categories. My products are in the final categorie and in the second level but not in the main one. When a customer reaches the "main" category, it looks to be empty but he can see the menu on the left side and go to any sub-category.
On the mobile version it is very different, there is NO such left menu. The customer reaches an empty category... with the message "there are no products in this category"... He can really think there is nothing at all.
So, I may solve the problem by adding ALL the products in the main category too.
By doing so, do I create a problem of "duplicate content" ???
In other words, should we add a same product do different categories at all or is it risky ?