What do "$m$" and "$d$" mean in the formula $F(A,B,C,D) = \Sigma m(9,10,12) + d(3,5,6,7,11,13,14,15)$?

Question

What do "$m$" and "$d$" mean here?

I know that "$\Sigma$" means sum of products but I do not know what "$m$" and "$d$" mean.

Please help.

Answer 1

It's the notation that comes along with a Karnaugh Map in boolean algebras.

$\sum m$ represents the canonical disjunctive normal form (CDNF) or minterm canonical form.

The numbers - called minterms - are the entries in the table that are 1.

The $d$ is used to indicate the don't-care entries.

Additionally $\prod M$ represents the maxterm canonical form, which identifies the entries that are 0.