Do they have a reason for doing so? I mean, in the sum of minterms, you look for the terms with the output 1; I don't get why they call it "minterms." Why not maxterms because 1 is well bigger than 0?
Is there a reason behind this that I don't know? Or should I just accept it without asking why?
Two dual canonical forms of any Boolean function are a "sum of minterms" and a "product of maxterms." The term "Sum of Products" (SoP or SOP) is widely used for the canonical form that is a disjunction (OR) of minterms.
If a Boolean function of multiple variables is expressed in Product-of-Sum terms, then each term is called the max term. That is the variable is taken as a logic “0” as we will see later. But first let us understand more what represents a Sum Term.
Sum of Products (SOP): These product terms are also called as 'min-terms'. Min-terms are represented with 'm', they are the product(AND operation) of boolean variables either in normal form or complemented form. Therefore, SOP is sum of minterms and is represented as: F in SOP = m(0, 3)
Minterm: A minterm is a product term in boolean function in which every element is present is either in normal or in complemented form. For example if F(a,b,c) is a boolean function then the possible minterms would be abc, abc', ab'c, ab'c', a'bc, ab,c, a'b'c, a'b'c' .
The convention for calling these terms "minterms" and "maxterms" does not correspond to 1 being greater than 0. I think the best way to answer is with an example:
Say that you have a circuit and it is described by X̄YZ̄ + XȲZ
.
"This form is composed of two groups of three. Each group of three is a 'minterm'. What the expression minterm is intended to imply it that each of the groups of three in the expression takes on a value of 1 only for one of the eight possible combinations of X, Y and Z and their inverses." http://www.facstaff.bucknell.edu/mastascu/elessonshtml/Logic/Logic2.html
So what the "min" refers to is the fact that these terms are the "minimal" terms you need in order to build a certain function. If you would like more information, the example above is explained in more context in the link provided.
Edit: The "reason they used MIN for ANDs, and MAX for ORs" is that:
In Sum of Products (what you call ANDs) only one of the minterms must be true for the expression to be true.
In Product of Sums (what you call ORs) all the maxterms must be true for the expression to be true.
min(0,0) = 0
min(0,1) = 0
min(1,0) = 0
min(1,1) = 1
So minimum is pretty much like logical AND.
max(0,0) = 0
max(0,1) = 1
max(1,0) = 1
max(1,1) = 1
So maximum is pretty much like logical OR.
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