Questions tagged [boolean-algebra]

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3
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2answers
128 views

Classical Computation without NOT

Is it possible to do universal classical computation using bits and 2-bit gates when you cannot perform a NOT operation on a single bit (hence cant do CNOT and so on). If yes, what are the possible ...
0
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1answer
1k views

Implementing a Boolean function with NOR gates

Implement f(a, b, c, d) = Σ m(3, 4, 5, 6, 7, 11, 15) as a 2-level gate circuit (a) Using OR gates and NOR gates. (b) Using NOR gates only. I have found that F=ab+d using Karnaugh map. I have also ...
1
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0answers
65 views

How does one calculate the block-sensitivity of a function?

I am looking at this paper : http://arxiv.org/pdf/1411.3419v1.pdf But somehow I am not being able to fish out a method to calculate this quantity called the "block-sensitivity". Can someone kindly ...
2
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1answer
92 views

Hardness of problem related to number of subsets that satisfy a particular property

I have the following algorithmic problem. I am given a set of elements. Each element has a set of properties. For example: ...
3
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1answer
35 views

Learning a small disjunction using an input distribution of our choice

I have a boolean function $f: \{0,1\}^n \to \{0,1\}$ that I know takes the form $$f(x_1,\dots,x_n) = x_{i_1} \lor x_{i_2} \lor \dots \lor x_{i_k}.$$ I don't know the values of $i_1,\dots,i_k$, but I ...
2
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1answer
132 views

Learning a small disjunction

I have a boolean function $f: \{0,1\}^n \to \{0,1\}$ that I know takes the form $$f(x_1,\dots,x_n) = x_{i_1} \lor x_{i_2} \lor \dots \lor x_{i_k},$$ but I don't know the values of $i_1,\dots,i_k$. ...
0
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1answer
106 views

Computing a boolean function with a small formula

Suppose that $x = (x_1,\ldots,x_n)$ is a binary vector and $f(x)$ is a boolean function. Furthermore suppose $y = (y_1,\ldots,y_m)$ is a binary vector and that $F(x,y)$ is a binary formula of size $...
1
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1answer
1k views

How do you produce a CNF from a circular graph with colouring?

If you had a circular graph e.g. A->B->C->D->E->A, and a legal coloring system with 3 colours (e.g. Red, Green Blue), where each node is assigned a colour and no node can be connected to another node ...
6
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1answer
227 views

Is there an intuitive proof for the existence of hard functions?

I am referring to the theorem on page 115 of the book by Arora and Barak, which states that, ``For every $n>1$, there exists a function $f:\{0,1\}^n \rightarrow \{0,1\}$ that cannot be computed by ...
-2
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1answer
585 views

A logic function that is true iff the first operand is less than the second operand

In my computer organization class I have been given a series of problems. One I'm stuck on currently is below: Assume that $X$ consists of 4 bits, $x_3 x_2 x_1 x_0$, and $Y$ consists of 4 bits, $y_3 ...
1
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1answer
189 views

Creating a single layer perceptron for the OR problem

I am working on the following problem Find the linear least squares unit weights for the `OR' problem, ie. $v_1^T = (0,0), v_2^T = (1,0), v_3^T = (0,1), v_4^T = (1,1)$ and $u_1 = 0, u_2 = u_3 = u_4 = ...
0
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1answer
1k views

Brackets in distributive law?

The (second) distributive law in boolean algebra is defined as $A + (B C) = (A + B) (A + C)$ But wouldn't it be correct to define it that way: $(A + (B C)\, ) = (A + B) (A + C)$ Because if you ...
3
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1answer
147 views

Couting Self dual functions

The Dual of a Boolean function $F(x_1, x_2, ..., x_n)$, written as $F^D$ is the same expression as that of $F$ with $+$ and $.$ swapped. $F$ is said to be self dual if $$F=F^D$$ How can we count ...
1
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0answers
24 views

Real versus Finite field polynomials

Let $f$ be a Boolean function. Let $g$ be the minimum degree real polynomial that represents $f$ with degree $d$. Let $g_{p}$ be the minimum degree $\Bbb F_p$ polynomial that represents $f$ with ...
0
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1answer
176 views

4-bit input, 5-bit output, logical right shift by 2, which is the correct set of 5 output bits?

Suppose I have the following inputs: 1110 1111 If I perform a logical right shift by 2 on each, are the 5-bit outputs these: 00111 00111 or these: 01110 01111 If it's neither, then I'd ...
0
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1answer
172 views

Example of a boolean function

Is there an example of real polynomial representation of a Boolean function with $4$ variables whose polynomial degree is $2$ that depends on $4$ variables?
1
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1answer
229 views

Lower bound on approximation degree in Nisan-Szegedy

In Nisan and Szegedy's 1994 paper "On the degree of boolean functions as real polynomials"[1] Lemma 3.8, how does proof work for $\widetilde{\deg(f)}\geq \sqrt{\,\tfrac16\mathrm{bs}(f)\,}$? It ...
1
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1answer
71 views

consider a base 16 adder how to modify the adder so that it can perform a base 8 addition?

Consider a base 16 adder. How can I modify the adder so that it can perform a base 8 addition? I expect this question will appear in my exam tomorrow; if anyone can give me a hint or a solution, I'd ...
0
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1answer
95 views

Prove that $\neg 0 = 1$

Starting from this definition https://en.wikipedia.org/wiki/Boolean_algebra_%28structure%29#Definition, is the following a valid proof that $\neg 0 = 1$? Instantiate a ∨ ¬a = 1 with a:=0 to get 0 ∨ ¬...
7
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1answer
1k views

Which CNF boolean formulas blow up exponentially at conversion to DNF?

If I'm correct, some boolean formulas in CNF require exponential size when being converted to an equivalent DNF version (and vice versa). But what is an example of such a formula (and is there a ...
1
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1answer
531 views

Parity function

How is the parity function defined in standard way if inputs are in $\{-1,+1\}$ instead of $\{0,1\}$. For $\{0,1\}$, parity is $x_1\oplus x_2\oplus\cdots\oplus x_{n-1}\oplus x_n$. I am looking for how ...
1
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1answer
92 views

How do you represent basic arithmetic using boolean function? [closed]

Say you have an arithmetic problem involving two variables, how do you give a Boolean formula for that using standard techniques so that one gets a minimal formula for a given number of quantifiers? ...
1
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0answers
107 views

Connection between formula size and time complexity

Supposing we have a problem $P$ with input size $n$ encoded as a boolean formula $f$ in $n$ variabes which is a multilinear polynomial. Let $f$ have the smallest degree. Is there a connection between ...
5
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2answers
948 views

Sensitivity and Block sensitivity

May be this question is really silly and obvious but I am missing something subtle. I am reading on Sensitivity and Block sensitivity. Let $f:\{0,1\}^n\rightarrow \{0,1\}$ be a Boolean function. Let ...
1
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1answer
78 views

Function with minimum sensitivity

Let sensitivity be defined as in Sensitivity and Block sensitivity Is there an example of a boolean function in $n$ variables that depends on all $n$ inputs whose sensitivity is $O(\log n)$? Is ...
1
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0answers
58 views

How do I triangularise a netlist?

I have a circuit that is represented as a netlist (specifically, an and-inverter graph). The desired outputs of this circuit are known. We can assume that some combination of the primary inputs will ...
1
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1answer
38 views

Comparing coefficients of boolean functions

Let a real polynomial representing a boolean function be $P(x_1,\dots,x_n) = \sum_{a\in\{0,1\}^n}c_ax^a = \sum_{a\in\{0,1\}^n}p(a)\prod_{i\in 1_a}x_i\prod_{j\in \bar{1}_a}(1-x_j)$ where $1_a$ is the ...
2
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1answer
251 views

Can the Euclidean distance function be computed using only XOR's

The Eulidean distance function $d$ of $x$ and $y$ is given by: $ d(x,y)=\sqrt{x^2-y^2} $ Let us assume that $x$ and $y$ are fixed-point numbers, or $x,y$ are element of some subfield $f_n$ of $F_p$. ...
1
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0answers
54 views

What is the current state of research on the representation of boolean functions using wavelets

The harmonic representation of boolean functions such as XOR or AND has been studied in different course note lectures that can be found on Google. http://cs.mcgill.ca/~hatami/comp760-2011/ http://...
2
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2answers
259 views

Is my simplified explaination of the XOR swap correct?

The XOR swap is a well-known in-place algorithm to swap two values, by XOR:ing them bitwise. It goes as follows: a = a ^ b b = a ^ b a = a ^ b Now, I was ...
2
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2answers
145 views

What is the state of the art in efficient boolean function operations?

How do you most efficiently combine boolean functions with a large number of variables using AND, OR, and NOT? The most up-to-date work that I can find on this subject is about 20 years old (...
1
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1answer
47 views

Reducing a system of two boolean algebra assertions to a single one

Given a system of two Boolean Algebra equalities a = b. c = d. one can exhibit a single equation F(a,b,c,d) = 0. which is ...
10
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2answers
3k views

Are Boolean functions Turing complete

A Boolean function is a function $f:\{0,1\}^n\rightarrow\{0,1\}$. The boolean basis $(\vee,\wedge)$ is known to be Turing complete as it allows any sequence $s\in\{0,1\}$ to be flipped or to be left ...
1
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0answers
129 views

Simplifying circuits using boolean algebra

I am having a lot of trouble simplifying my circuit using boolean algebra. I am very new to this and any explanation would be greatly appreciated. I have y'+z+w'x+wx' I feel like I could use DeMorgan'...
5
votes
1answer
213 views

Finding a graph-theoretic representation of expressions in Boole's algebra

I just read "Boole's Algebra Isn't Boolean Algebra" by Theodore Halperin (behind a paywall here). I don't have a strong background in abstract algebra, so, frankly, the paper is a bit over my head but ...
0
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1answer
1k views

Odd Parity Function [closed]

I am trying to define a Odd Parity Function that takes three 1 bit inputs and will output a 1 if the 3 bits are odd as a Boolean function. ...
8
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0answers
149 views

Boolean formula that agrees with most truth assignments

Let $X_1,\dots,X_n$ be $n$ boolean variables. I have an unknown predicate $P(X_1,\dots,X_n)$ on these boolean variables. Of course, I can view the predicate as a function $f_P : \{0,1\}^n \to \{0,1\}...
4
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1answer
415 views

Issue understanding the reduction of SAT to 3-SAT in poly time

Reading this http://classes.soe.ucsc.edu/cmps102/Spring10/lect/17/SAT-3SAT-and-other-red.pdf, I came to know that reducing a clause $C_i$ from a $SAT$ instance containing more than 3 literals to a $3-...
2
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1answer
264 views

Recognizing Horn clauses

I am currently studying model theory and I am trying to decide if a clause is a Horn Clause. I know that a Horn Clause is a clause with at most one positive literal, but there are some clauses that it ...
1
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0answers
121 views

Popcount Orders and Lexicographic Orders [closed]

A popcount order of a two bit vector {1,1}=3 can be given by: {{1, 1}, {1, 0, 1}, {1, 1, 0}, {1, 0, 0, 1}, {1, 0, 1, 0}, {1, 1, 0, 0}, {1, 
 0, 0, 0, 1}, {1, 0, 0, 1, 0}, {1, 0, 1, 0, 0}} and as a ...
1
vote
1answer
382 views

Laws to simplify a boolean formula

$$ (\neg A \wedge \neg C) \vee (\neg A \wedge D) \vee (\neg A \wedge B) \vee (\neg B \wedge \neg C) $$ can simplify down to  $$ (\neg A \wedge D) \vee (\neg A \wedge B) \vee (\neg B \wedge \neg C) $$ ...

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