# What does it mean: “Assuming a matrix | Use a list of lists instead”?

I have entered a matrix by Insert->Table/Matrix->New.

After adding it to code, Mathematica wrote a remark: "Assuming a matrix | Use a list of lists instead".

Value is already looks as list of lists. Clicking "list of lists" does not change anything visible.

• In Mathematica, a matrix is just a list of lists, so don't worry. This just means that the suggestions bar offers suggestions for matrices. If you clicked on "list of lists", you'd see different suggestions. – Niki Estner Nov 18 '14 at 11:53
• strictly, a matrix must be 2d with equal length sub lists. functions such as linearsolve will only take proper matrices. – george2079 Nov 18 '14 at 12:33