sum of products (SOP), product of sums (POS)

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Joined Apr 15, 2011

There exists two standard forms of Boolean expression as far as I know: Sum of Products (SOP) and Product of Sums (POS). I understand that SOP is implemented by AND and OR gates. The outputs of AND gates are ORed. For POS outputs of OR gates are ANDed.

Q1: It is said that these standard forms are simplified expressions. Please have a look on the attached page and please tell me what makes it simplified version. Thanks.

Q2: In case of SOP we are interested in only those terms (called Minterms) which result in "1" but in case of POS only terms (called Maxterms) which give us "0". Why is so? In case of POS one "0" term will give us the output "0".

Q3: It seems there are very strong relationship between SOP and POS. Please have a look here.

Q4: Please have a look here.

Thanks a lot for the help. It's very kind of you.



Last edited:


Joined Feb 24, 2006
The "simplification" results from being able to determine:

  1. All of the cases for which the output is a '1' (SOP)
  2. All of the cases for which the output is a '0' (POS)
You keep duplicating those textbook pages and you'll trigger a DMCA takedown notice. -- LOL