Questions tagged [circuits]

A computation model in which the computation is described via circuits of various logic gates.

Filter by
Sorted by
Tagged with
1
vote
0answers
40 views

Can you build a solver circuit from a verifier circuit?

Can you build a solver from a verifier? I see that if you start with an NP-verifier TM the answer is yes, you can build a solver TM. How about for circuits? Can you go from a circuit that implements a ...
1
vote
1answer
15 views

Functions with small support have small circuits

I have been trying to understand the use of circuit models for boolean functions, and came across this question, that I am trying to struggle to understand: Show that if a function $f\colon \{0,1\}^n→\...
0
votes
1answer
92 views

Is NP in NP/Poly?

The answer is yes, NP/poly is defined as the class of problems solvable in polynomial time by a non-deterministic Turing machine that has access to a polynomial-bounded advice function--the advice ...
-1
votes
1answer
15 views

single circuit simulating multiple Turing machines

You can simulate polynomial time Turing machines with polynomial size circuits, can you simulate multiple poly time TMs with a single poly size circuit?
0
votes
0answers
15 views

Simulation of circuits with circuits

From classical results of universal simulation of Turing machines there exists a Universal Turing machine simulating any Turing machine with time complexity 𝑇(𝑛) in time 𝑇(𝑛)log𝑇(𝑛). Is there is ...
-1
votes
0answers
36 views

Since P-Uniform = P does NP-Uniform (is there such a thing?) = NP?

A circuit family is $P−Uniform$ if there exists a polynomial time $DTM$ which on an input of $1^n$ outputs the description of $Cn$, the $n$th circuit. Presumably $NP-Uniform$ would look something like ...
1
vote
1answer
20 views

Hardness of boolean functions

For a boolean function $f:\{0,1\}^n\longrightarrow\{0,1\}$, $H_{avg}(f)$ is a function from $\mathbb{N}\longrightarrow \mathbb{N}$, termed as the average case hardness, if $\forall$ circuit $C_n$ of ...
1
vote
1answer
78 views

Connection between Pseudo random generators and hardness

For a boolean function $f:\{0,1\}^n\longrightarrow\{0,1\}$ $H_{avg}(f)$ is defined as the largest $S(n)$ s.t. for all circuit $C_n$ of size $S(n)$, $\Pr_{x\in U_n}[C_n(x)=f(x)]<1/2+1/S(n)$. Here $...
1
vote
1answer
66 views

Existence of boolean function with exponential average case hardness

Show that for every large enough $n$, there is a boolean function $f\colon \{0,1\}^n\longrightarrow\{0,1\}$, whose average case hardness is exponential. The question is taken from Arora Barak ...
0
votes
0answers
68 views

Prove that the number of circuits with bounded fan-in (of 2) of size $s$ is at most $s^{O(s)}$

Prove that the number of circuits with bounded fan-in (of 2) of size $s$ is at most $s^{O(s)}$. Give the best explicit bound you can get. I know that for a circuit of size $s$ in order to generate a ...
2
votes
0answers
34 views

Circuit complexity of hardest monotone function

Show there exists a monotone function $f\colon \{0,1\}^n \mapsto \{0,1\}$, such that the minimal size of a monotone circuit that computes $f$ is $\Omega(2^n / n^2)$. Use the fact that the number of ...
5
votes
1answer
50 views

Is there a polynomial sized arithmetic formula for iterated matrix multiplication?

I found an article on Catalytic space which describes how additional memory (which must be returned to it's arbitrary, initial state) can be useful for computation. There's also an expository follow ...
1
vote
2answers
50 views

Show that the OR of n variables cannot be expressed as a polynomial over Fp of degree less than n

Here is a question from Computational Complexity by Arora and Barak: Show that representing OR of $n$ variables $x_1,x_2,\dots,x_n$ exactly over a polynomial in $GF(q)$ requires degree exactly $n$. (...
1
vote
0answers
24 views

Why mod $p$ gates cannot be computed by $ACC^0[q]$ circuits, $p$ and $q$ prime

I am going through Computational Complexity by Arora and Barak, and there I came across the proof of why mod $p$ gates cannot be computed by $ACC^0[q]$ circuits, where $p$ and $q$ are distinct primes. ...
0
votes
1answer
36 views

For a logic gate to be universal, must it necessarily be able to perform duplication?

It is said that a gate that can simulate AND and NOT is universal and able to recreate any classical circuit. I was looking at some of the circuits simulated by NAND, and for some of them, we need to ...
0
votes
0answers
12 views

Question about numbering of internal nodes in circuit diagrams when one circuit element has more than 1 internal node

I have the following circuit diagram that I've added labels for the internal nodes to using outside sources. I understand what an internal node is, however what I'm confused about is-- for example-- ...
2
votes
1answer
63 views

Counting circuits with constraints

Please forgive me if this question is trivial, I couldn’t come up with an answer (nor finding one). In order to show that there are boolean functions $f : \{0,1\}^n \rightarrow \{0,1\}$ which can be ...
0
votes
1answer
25 views

What is the difference between SIZE(n^k) and P/poly?

What is the difference between $\text{SIZE}(n^k)$ and $\text{P}/\text{poly}$? For reference: $\text{SIZE}(n^k)$ is defined as the class of problems solvable with Boolean circuits (of fan-in two) with ...
1
vote
1answer
49 views

What can this circuit be useful for?

I have calculated the boolean functions for $r$ and $f$: $f = \overline{s_1} \cdot s_0 + s_1 \cdot \overline{s_0}$. $r = \overline{s_0 \cdot s_1 \cdot s_2 \cdot s_3}$. Do you have an idea what an ...
4
votes
1answer
48 views

Can the W hierarchy by defined by circuits having a satisfying assignment of weight at most k?

Traditionally, the $W$ hierarchy is defined around the problem of weighted circuit satisfiability. More precisely, the class $W[t]$ is defined as the closure under $\mathrm{fpt}$-reductions of the ...
2
votes
1answer
53 views

Construct a Circuit computing all boolean functions over n bits

Let $ n∈N $ . Construct a circuit with $ C_n(x_1,\dots,x_n) $ with $ 2^{2^n} $ outputs $ y_1,\dots,y_{2^{2^n}} $ which computes all distinct boolean functions $ f_i:\{0,1\}^n→\{0,1\}$ such that $ ...
0
votes
1answer
32 views

Problem with understanding Multi-party security circuit for secure stable matching

I am reading the following paper: MPCircuits: Optimized Circuit Generation for Secure Multi-Party Computation Paper Link I have following question: We have two groups shown in the circuit. Why we ...
0
votes
1answer
19 views

How to prove quantum circuit identity in Qiskit?

I am working on a simple quantum circuit identity. I proved it on paper with the tensor product, but i'm having trouble showing that with qiskit. I know I need to measure them somehow but i don't know ...
1
vote
2answers
53 views

Proof that uniform circuit families can efficiently simulate a Turing Machine

Can someone explain (or provide a reference for) how to show that uniform circuit families can efficiently simulate Turing machines? I have only seen them discussed in terms of specific complexity ...
1
vote
0answers
185 views

Example of *small* non monotone circuit such that any equivalent monotone circuit has greater size?

A "general" Boolean (combinatoiral) circuit is a labeled (with the labels: AND, OR, NOT, IN, OUT), directed, acyclic graph, that satisfies: fan-in=2 for the AND and OR nodes fan-n=1 for the NOT ...
2
votes
1answer
73 views

Is it assumed that lower bounds on the size of monotone circuits apply to general Boolean circuits too?

A "general" Boolean (combinatoiral) circuit is a labeled (with the labels: AND, OR, NOT, IN, OUT), directed, acyclic graph, that satisfies: fan-in=2 for the AND and OR nodes fan-n=1 for the NOT ...
1
vote
0answers
17 views

Examples of relatively complex truth tables/logic gates in real life?

I'm researching truth tables, logical gates, and boolean algebra expressions. I'm trying to find specific real-life examples of logic gates and/or truth tables used in algorithm or circuit design in ...
2
votes
1answer
56 views

Multiplication mod 2 without extra registers

For an arbitrary bitstring $(x_1, x_2,\ldots, x_n)$ and an $n\times n$ invertible binary matrix $M$ (fixed ahead of time), I would like to construct a circuit $C$ acting on these $n$ bits whose output ...
1
vote
0answers
15 views

Boolean circuit multigraph

Let us say that our definition of a circuit is the one of a boolean circuit from [Vollmer]. He uses directed acyclic graphs to represent circuits where the computation nodes are labeled with some ...
2
votes
0answers
55 views

Are minimum boolean circuit sizes for small problem sizes of an NP-complete problem known?

I think that a table with the following numeric values would be very interesting, but I could not find any table online displaying them: Choose any NP-complete problem (say, clique, but a problem ...
0
votes
0answers
52 views

How does this circuit work?

I saw a Computerphile video explaining how a simple circuit could store memory using some logic gates. However, I couldn't wrap my mind around how one could find the value of q if one needs not, ...
3
votes
1answer
35 views

Lower bound on number of (different) circuits of given size?

For circuits with $n$ input bits, we know that, for any function $s$, there are at most $O(s(n)^{s(n)}) = O(2^{s(n) \log s(n)})$ circuits with size at most $s(n)$. Say two circuits $C_1$ and $C_2$ ...
1
vote
1answer
29 views

Relationship between circuit size and formula size in Sipser text

The Sipser text (3rd edition) contains a proof that 3-SAT is NP-Complete based on Boolean circuits. Part of the proof contains the remark that the reduction from the circuit to the Boolean formula can ...
0
votes
0answers
11 views

Circuit : Switching function. Can I ignore RESET and CLOCK for the functions?

So if I have to state any function like state transition function or switching function can I ignore CLOCK and RESETS?
2
votes
0answers
85 views

Class of languages recognizable by n-bit formulas of size at most $T(n)$

A Boolean (combinatoiral) circuit is a labeled (with the labels: AND, OR, NOT, IN, OUT), directed, acyclic graph, that satisfies: fan-in=2 for the AND and OR nodes fan-n=1 for the NOT nodes fan-...
2
votes
0answers
41 views

Circuit complexity of random Boolean functions

I just saw a YouTube video where Ryan Williams gives a talk about circuit complexity. He stated that random Boolean functions require exponential size circuits to compute, but I don't understand why ...
0
votes
1answer
26 views

Is this truth table possbile

I am trying to figure out if this truth table is possible. I've tried inverting the numbers, adding them, subtracting them, but I still cant find anything that works. I am starting to think that this ...
1
vote
1answer
59 views

What is $f(n)$ in $NTIME(n)\subseteq DTIME(f(n))$ if $CIRCUITSAT$ is in $P$?

If $CIRCUITSAT$ in $n$ variables and $m$ gates has an $O((nm)^c)$ algorithm for a fixed $c>0$ then $NTIME(n)\subseteq DTIME(O(f(n)))$ for large enough $f(n)$. What is the smallest $f(n)$ in $NTIME(...
2
votes
0answers
22 views

Simulating Boolean Circuit with RAM

Statement: Every $T(n)$ size bounded Boolean circuit family, could be simulated with $(T(n))^2$ time bounded Random Access Turing Machine (RAM). Could you please supply me with a reference to an ...
0
votes
0answers
24 views

Which gates are “pre computation” universal?

In the following, by “functions” I will mean 2 input 1 output Boolean logic functions (for conciseness). A function is called “universal” if by using it (sometimes multiple times, chained together), ...
1
vote
2answers
229 views

Nandgame--I am not sure I understand the Data Flip-Flop specifications

Nandgame (nandgame.com) has you solve puzzles of increasing complexity which culminate in constructing a simple CPU. You start at the level of nand gates, and build everything else up out of those. I'...
-1
votes
2answers
49 views

Minimize circuit functions

$\begin{array}{rrrr | rr } 0& 0 & 0 & 0 & 1 &1 &1 &1 &1 & 1&0 \\ 0& 0 & 0 & 1 & 0 &1 &1 &0 &0 & 0&0 \\ 0& 0 & 1 &...
1
vote
1answer
50 views

What does it mean when a dot appears in a logic gate other than the NOT gate? (in logic diagrams)

For example, this gate: looks like an OR gate, except there's a dot to the right. The dot is reminiscent of the fact that there's a dot in the NOT gate, so I wonder if it has something to do with ...
2
votes
1answer
155 views

Addition, multiplication, and apostrophe used to represent boolean algebra expressions?

I'm looking at a worksheet that expresses boolean logic expressions using multiplication, addition, and apostrophes; something I've never seen before. I can make a guess that the apostrophe is ...
4
votes
0answers
110 views

Perfect Halver Construction?

A sorting network is a circuit-based approach to sorting, built out of CompareExchange gates, which compute the function: $$\mathsf{CompareExchange}(x,y) = (\min(x,y), \max(x,y))$$ The input to the ...
2
votes
2answers
49 views

How to show all false outputs in a circuit?

I have 3 input variables and the output for all 8 possible combinations is 0 (false). When making a circuit, how would I show this using gates or no gates at all? Thanks!
5
votes
1answer
70 views

How does $\mathsf{NP} \subset \mathsf{P}/\mathsf{poly}$ imply these two inclusions?

In the proof of Theorem 1 in this paper by Chen, McKay, Murray, and Williams the authors assume $\mathsf{NP} \subset \mathsf{P}/\mathsf{poly}$ and (in different parts of the proof) state this implies ...
0
votes
1answer
58 views

Number of circuits with at most $m$ logic gates

I'm working on the same exercise as described in this post: How to show that hard-to-compute Boolean functions exist? In the answer there I don't understand how the number of circuits with at most $...
0
votes
1answer
26 views

What is the difference between a collection of Turing Machines and a family of Circuits?

Given a Collection of Turing Machines $T_1, T_2, T_3,...T_n$ where $T_1$ denotes that the Turing machine can only take in an input of size 1. Is there any difference in computational power to a family ...
2
votes
0answers
42 views

Does Cook and Ruzzo's result also hold for logspace-uniform AC0?

In Cook's famous paper on $\mathsf{NC}$, he cites the following result: PROPOSITION 4.7 (Cook and Ruzzo, 1983). $\mathsf{AC}^k$ consists of those problems solvable by uniform unbounded fan-in ...

1
2 3 4 5