Boolean algebras are structures which behave similar to a power set with complement, intersection and union. Questions regarding Boolean algebras as structures, or regarding functions defined from/to Boolean algebras fit into this tag very nicely. For Boolean logic use the tag propositional logic

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Finding number of Boolean algebras

How many Boolean algebras are there with four elements $0,1,a,b$ ? I don't know how to proceed with this. Any ideas ?
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Converting large terms to disjunctive normal form (logic)

So hello everyone, I am doing some boolean logic and I have this exercise to convert the following term to DNF (disjunctive normal form), but it is so large that everything I try ends up being mega ...
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Is it possible to express “$P\leftrightarrow Q$” as a formula in $\to,\neg$ with $P$ only appearing once?

I want to write a propositional logic formula for the biconditional that only uses one side of the biconditional once in the formula. I expect it is impossible, but can anyone think of a proof? There ...
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Finding a simple function for a given Karnaugh diagram

I came across one question in which the Karnaugh map for some function is given and using it, i have to find a simple function which gets mapped onto that map. My Attempt: Corresponding to every ...
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How to define equivalency as NAND only function?

I am struggling a bit with boolean algebra. I need to represent equivalency as NAND only function. $(A * B) + (-A * -B)$ I am trying with the Morgan rule but I don't know if I can do that: $(A * ...
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how many semantically different boolean functions are there for n boolean variables?

In short, this is an assignment question for a course I am taking - the exact wording is this: "Given n Boolean variables, how many 'semantically' different Boolean functions can you construct?" ...
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Truth-functional completeness

Let the statement $?PQR$ be determined by the following truth-table. ...
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Peculiar examples to the Stone Representation Theorem

The Stone Representation theorem states that every Boolean algebra is isomorphic to a field of sets. That is, a Boolean algebra whose elements are sets, and sums, products, negation are union, ...
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Need help proving that $ fRg \Leftrightarrow fg = f $ on $ B^{n} $ to $ B $ if and only if $ f(b_1,…,b_n) \leq g(b_1,…,b_n) $

I'm trying to gather my thoughts for proving the following claim: For $ fRg \Leftrightarrow fg = f$ on $B^{n}$ to $B$, show that $ fRg $ if and only if for any input values $ b_1,...,b_n $, we ...
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How can I rewrite this xor formula to generate cnf formulas

$$ \bigwedge_{c=1}^n\bigwedge_{i\epsilon S}\bigoplus_{r=1}^nX_{irc} $$ I have tried $$ \bigwedge_{c=1}^n\bigwedge_{i\epsilon S}\bigwedge_{r_1=1,r_2=1}^n(X_{ir_1c}\vee X_{ir_2c})\wedge(\neg ...
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Simplify this boolean algebra?

$$ \begin{align} &\lnot x_1(x_2\land\lnot x_3\lor x_3)\lor x_1(\lnot x_2\land\lnot x_3\lor x_2\land x_3)\\ &=\lnot x_1\land x_2\land\lnot x_3\lor\lnot x_1\land x_3\lor x_1\land\lnot ...
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Boolean Logic - Reduction - $a \vee (a \wedge b) = a$

How would I simplify / reduce the following equation using boolean identities/proofs? $$a \vee (a \wedge b) = a$$ So far I've used the distributivity identity and got $$(a\vee a) \wedge (a\vee b)$$ I ...
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Do brackets around negation signify negating the input or output - Boolean Algebra Logic Circuits

I know that $\overline{p + q}$ will result in the input to the logic gate being p, and q, and we can negate this by using an or gate, followed by a not gate, or we can just use a nor gate. However, ...
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If $A_1\cap…\cap A_n \neq \emptyset$, does $(A_1\cap…\cap A_n)^{c} =A_1^{c} \cup … \cup A_n^{c} = \emptyset$?

If I have some collection of sets such that $A_1\cap...\cap A_n \neq \emptyset$, then what happens if I apply the complement (denoted by superscript c) to both sides? i.e., $(A_1\cap...\cap A_n)^{c} ...
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Boolean algebra. For all x, y, and z in B, if x + y = x + z and x × y = x × z, then y = z.

In the statements below, $B$ is a Boolean algebra with $\times$ and $+$ for binary operations and ($\bar{a}$)is the complement of $a$. 4.) For all $x$, $y$, and $z$ in $B$, if $x + y = x + z$ and $x ...
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Applying De Morgans Laws to $a+bc+\overline{a}b\overline{c}d$ in terms of the NOR operator

I need to synthesize $f=a+bc+\overline{a}b\overline{c}d$ into the NOR form. Can I split this since I know that $a+bc=(a+b)(a+c)=\overline{\overline{a+b}+\overline{a+c}}$? I'm just not sure how to go ...
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Why is this a boolean algebra

Let $A = \{a,b\}$. The $\mathcal P(A) = \{\emptyset,\{a\},\{b\},A\}$. Let $+$ be $\cup$, $\cdot$ be $\cap$, complement be set complement, $1$ be $A$, and $0$ be $\emptyset$. I need to explain why ...
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How can i turn the Boolean Equation pq+r into a switch circuit?

How can I turn the Boolean Equation $pq+r$ into a switch circuit? I have synthesized this and drawn the NOR gates circuit however I'm not sure how to go about drawing/constructing the switch circuit.
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Applying De Morgan's to express $pq+r$ in terms of NOR operator

In Boolean Algebras I have $pq+r$ which I think is the same as $(p+r)(q+r)$. Now, I need to use De Morgan's laws to synthesize this into the NOR form but I am not sure how to apply the laws here.
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Why is chosen for intersection instead of union?

Constructing a commutive monoid having idempotent elements (the underlying monoid of a Boolean ring) free over a set $X$, I arrive on a very natural way at monoid $M$ having the finite subsets of $X$ ...
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Zhegalkin polynomial Boolean algebra

I have to find the Zhegalkin polynomial of $ (x\rightarrow y)\rightarrow z $. Please tell me if this is right: my polynomial is of this kind $ a_{0} + a_{1}x + a_{2}y + a_{3}z + a_{4}xy + a_{5}yz + ...
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Proving hypothetical sylloligism (p implies q, q implies r, therefore p implies r) with boolean algebra

I'm trying to prove the hypothetical sylloligism using boolean algebra. We already have a solution using propositional logic, which relies on proof by contradiction. $(p \implies q) \wedge (q ...
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Terminology: algebras, sigma-algebras, complete algebras…

There are 2 things which create a lot of confusion in my mind. 1) I know that every sigma-algebra is an algebra. But not every algebra is a sigma-algebra. Put differently, it seems that ...
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AND using XOR and OR?

Is there a way to make an AND using only XOR and OR. I know that a XOR b = ab'+ba' but I have no idea how to proceed. Could it be impossible?
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How to simplify following boolean expression? A+A'BC+BC'?

please help I'm stuck. I'm trying to solve this. so far I have: a) a+b+c b) a+bc c) a+b d) a+b but for e) I can't progress further since I don't know how to deal with a'bc in this case. ...
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Finding conjunctive normal form of a Boolean polynomial

I have to find the conjunctive normal form of the following Boolean Polynomial : $(x_1+x_2+x_3)(x_1x_2+x_1'x_3)'$ I simplified this polynomial to get $x_1x_2'+x_1x_2x_3'$ for which i then formed the ...
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Boolean Algebras

simplify: (1) $f= pq+r$ (2) $g=a+bc+a'bc'd$
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Boolean Simplification of A'B'C'+AB'C'+ABC'

My question is how do I reduce A'B'C'+AB'C'+ABC' (note that (') stands for a bar over the letter). To get (A+B')C'. I'm so lost just been trying to get it for awhile only using the 10 boolean ...
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Simplification of a boolean polynomial

I have to simplify the following Boolean polynomial using $x\land y$ = $xy$ and $x\lor y$ = x+y : $xy'+x(yz)'+z$ =$xy'+x(y'+z')+z$ =$xy'+xy'+xz'+z$ =$xy'+xz'+z$ My book gives the following ...
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Boolean Simplification (ABCD)' + ((CD)'(B+D)'

I have to simplify (ABCD)' + ((CD)'(B+D)' function using boolean algebra. I simplified it using a truth table and got ...
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A boolean algebra is complete if its stone space is extremally disconnected

I have the following proof, but I don't understand one of the steps: Theorem 4.4. A Boolean algebra is complete iff its Stone space is exlremally disconnected. Proof. Identify the given ...
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Semantic consequence

I'm studying refutation trees in computer science II, but I have a big doubt: Let $\Gamma, \Psi \subseteq F_m$ Is the following hypothesis true? $\Gamma \vDash \Psi \iff \not\vDash\{\Gamma,\lnot ...
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Boolean Expression simplification help

Hi I am new to the board. Taking a computer architecture course and I am having trouble understanding further simplification on a question I got on a previous quiz. When I type in the expression ...
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Convert boolean expression into SOP and POS

Convert the following expression into SOP (sum of products) and POS (product of sums) canonical forms using boolean algebra method: $(ac + b)(a + b'c) + ac$ Attempt at solution: $(ac + b)(a + b'c) ...
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Boolean Simplification for Kmap

Diclaimer: This is not a homework assignment, it's a practice sheet that already has answers provided and is not graded in any way, however the steps are not shown hence the question. I'm having ...
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Boolean algebra simplification.

I start with: $$\bar{A}\bar{B}\bar{C}+\bar{A}BC+A\bar{B}\bar{C}+A\bar{B}{C}=A\bar{B}+\bar{B}\bar{C}+\bar{A}BC$$ then I did: ...
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Boolean Function with ^ and or

Please provide feedback on my answer to this question. Question: Prove that not every boolean function is equal to a boolean function constructed by only using ^ and or. Answer: True, Suppose that a ...
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Boolean algebra question.

Is there a way to show that $$A\bar{B}C\bar{D}+D=A\bar{B}C+D$$ using the rules of boolean algebra? I tried several methods such as expanding D with $$D(D+\bar{D})$$ or adding $$D\bar{D}$$ to the ...
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How to solve this boolean algebra problem?

Given two expressions: $$A\bar{D}+A\bar{C}D +A\bar{B}C + ABCD = Y$$ and $$BD+A\bar{C}D=Z$$ is there a way to simplify this using the rules for Boolean Algebra? I tried different combinations, but if I ...
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Can covering be done on two elements?

The covering rule is: $$B \bullet (B+C) = B$$ and $$B+(B \bullet C)=B$$ So does it follow from this rule that: $$B \bullet A \bullet \bar{C} + B \bullet D \bullet\bar{F} = B \bullet ...
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Arrow's Impossibility Theorem Using Boolean Algebra

I am currently working on a research project which involves using Boolean matrices for the proof of Arrow's Impossibility Theorem and various other lemmas and results related to quasi ordered sets. In ...
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Boolean Least Squares semidefinite relaxation

So I'm working on the Boolean least squares problem that comes up a lot in circuit design. In its raw form, it looks like this, $$\phi = \min \operatorname{trace}(A^TAX) - 2b^TAx + b^Tb$$ s.t. $$X = ...
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Simplify Product of Sums

Similar question to: Boolean Algebra - Product of Sums I was given a truth table and asked to give the sums-of-products and the product-of-sums expressions. I reduced the sums-of-products ...
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Proving Boolean Functions

Please check my answer to this question and give me feedback . Question: Either exhibit 333 different boolean functions on the three variables p,q,r, or prove that there aren't 333 different such ...
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Boolean Functions with p,q,r

Please give me feedback for my answer to this question. Question: (1) Are the boolean functions $(p \land \neg q) \lor ( \neg r \land q)$ and $(p \lor \neg q) \land (r \lor \neg q)$ equal?. Explain ...
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Construct XNOR with only OR gates

Is it possible to construct the XNOR gate which is given as, a XNOR b = (a AND b) OR (~a AND ~b), by using only OR gates. So from the definition, the question boils down to: can you construct the AND ...
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Boolean-like algebra

Suppose one had an algebra that that follows most of the laws of Boolean algebra (associative, commutative, distributive, identity, annihilator, idempotent, double negation, De Morgan) but does not ...
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A well-defined operation on measure algebra

Let $(X,\cal{M},\mu)$ be a measure space, and for $E,F\in \cal{M}$ write $E \sim F$ iff $\mu(E \Delta F)=0$. Let $\widetilde{\cal{M}}$ be the set of equivalence classes in $\cal{M}$ for $\sim$; for ...
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How to prove the divisors of 15 form a Boolean algebra

This from Exercise 3.1 in "A Beginner's Guide to Discrete Mathematics" Let B be the set of all positive integer divisors of 15, that is B = {1, 3, 5, 15}. Prove that B forms a Boolean algebra with ...
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Prove if Tautology, Contradicton, or Neither. Is my proof ok?

Determine whether $((p \Rightarrow q) \Rightarrow r) \Leftrightarrow (p \Rightarrow (q \Rightarrow r))$ is a tautology, a contradiction, or neither. If $p,q,r = (0,0,0)$ then $((p \Rightarrow ...