Well I'll write my problem down.

(0,1,2,5,6,13,1)_{1}(3,9,12)_{-}

In my discrete maths homework I had to find minimal DNF through Karnaugh map and got: -X_{1}-X_{2 }v -X_{3}X_{4}v -X_{1}X_{3}-X_{4}v X_{1}X_{2}X_{4 }( "-" infront of X means inversion)

Then I needed to find CNF via McCluskey's method which I got: (-X_{2}v X_{3}v X_{4})&(X_{1}v -X_{3}v -X_{4})&(X_{2}v -X_{3}v -X_{4})&(-X_{1}v X_{4}).

The next task was to transform the CNF from McCluskey method to DNK. After I did that (lots of work opening the brackets) I got:

-X_{1}-X_{2}-X_{3}v -X_{1}X_{3}-X_{4}v X_{1}X_{2}X_{4}v -X_{1}-X_{2}-X_{4}v -X_{3}X_{4. }Now I did the prime implicant chart and finished up with this: -X_{1}-X_{2}-X_{3}v -X_{1}X_{3}-X_{4}v X_{1}X_{2}X_{4}v -X_{3}X_{4. }The task was that the DNF I fould from Karnaugh map and the one I got from making CNF to DNF must be logically equal, but however many times I tried, they werent, and one implicant wasnt needed. They are almost the same, only in the -x1-x2 from karnaugh map the result after implicant chart was -x1-x2-x3 and I have no idea what to do. Done it throught 3 times already and checked for errors. any help?

I made a truth table, and yes 1 of 16 was different. The f(0011) which is 3_{10 }and is in the_{- }zone.

Lots of thanks, if someone can help me !