I have the follwing question in homework: Let $ G = (V,E)$ be Undirected graph, And let $ A$ be $ A$ = {$ e ∈ E$ | there exists msp $ T$ such that $ e ∈ T$ }. We were asked to find A in $ O(|E|log(|V|)$ . Any suggestions?

# Tag: exists

## Problem in NP: $EQ1 = \{(p_1,…,p_n): \exists x_1,…,x_m\in Z \ p_1(x_1,…,x_m)=…=p_n(x_1,…,x_m)=0. \}$

I have to following problem to show is in NP class.

$ EQ1 = \{(p_1,…,p_n): \exists x_1,…,x_m\in Z \ p_1(x_1,…,x_m)=…=p_n(x_1,…,x_m)=0. \}$

Here $ p_1,…,p_n$ are polynomials in m variables with integer coefficients.

I know how to proof EQ1 is in NP, but I confess I have not understood what is the instance accepted by the problem EQ1 (all polynomials are unsoddisfacible?)

## What is the time complexity of determining whether a solution $x$ exists to $x^k \equiv c \pmod{N}$ if we know the factorization of $N$?

Suppose we are given an integer $ c$ and positive integers $ k, N$ , with no further assumptions on relationships between these numbers. We are also given the prime factorization of $ N$ . These inputs are written in binary. What is the best known time complexity for determining whether there exists an integer $ x$ such that $ x^k \equiv c \pmod{N}$ ?

We are given the prime factorization of $ N$ because this problem is thought to be hard on classical computers even for *k* = 2 if we do not know the factorization of $ N$ .

This question was inspired by this answer, where D.W. stated that the nonexistence of a solution to $ x^3 \equiv 5 \pmod{7}$ can be checked by computing the modular exponentiation for $ x = 0,1,2,3,4,5,6$ , but that if the exponent had been 2 instead of 3, we could have used quadratic reciprocity instead. This lead to my discovery that there are a large number of other reciprocity laws, such as *cubic reciprocity*, *quartic reciprocity*, *octic reciprocity*, etc. with their own Wikipedia pages.

## Is any key signing party directory – or a mean to facilitate such meetings, exists?

I need to develop my web of trust. I don’t live in or near a metropolitan area and as such it is a bit difficult to find possible local people to sign. I assume I must not be alone in that context.

My question: is there any directory/listings of upcoming gpg-signing party per area, or any existing infrastructure to facilitate such meetings? Or alternative ways to find / meet people who can sign?

## What is the probability that an expanding bipartite graph exists with the property, |V1|=|V2|?

I want to find a bound on the above problem, and show that a random graph has a positive probability of being an expanding bipartite with the property, |V1|=|V2|. I am not getting, where should I start.

Apologies for not writing my understanding, I am very much stuck.

## No FSM/Regex exists for this language right?

The language is this:

$ L = \{w \in \{a,b\}*:$ each $ a$ has a matching $ b$ somewhere in $ w$ $ \}$

This wouldn’t have an FSM since you’d need infinite states of depth for each unmatched a you have, right?

## Why often exists a divider line between between a sign up and a login form?

Why is it needed a divider line between these two forms? Isn’t proximity enough to group each individual form elements and make each a group? Or is it needed because, since they are sharing the same background but are conceptually different things(a login and a signup), they are being wrongly perceived as a single unit due to the common region gestalt principle and hence need some separation?

## How to check if an item exists on a SharePoint list

I have a list (List A) which allows people to submit items. I have another list (List B) with specific individuals on it

I want to create a workflow which when an item is submitted on List A, it will lookup the created by field for the item against the list of names in List B.

If it is a match an email will be sent to both me and the individual who created the item in List A Then the list item in List A will be deleted.

Any idea if this is possible using a SharePoint 2010 workflow and sharepoint designer 2010 I am using sharepoint server 2016 **NOT** sharepoint online

## JAVA DEPLOY – FAIL – Application already exists at path /MiProyecto

Estoy trabajando en un proyecto en Java ICEfaces, cuando trato de hacer deploy me da el siguiente error:

OK – Undeployed application at context path /MiProyecto In-place deployment at C:\MiProyecto\MiProyecto\build\web deploy?config=file:/C:/Users/JULIAN~1.COR/AppData/Local/Temp/3/context48767.xml&path=/MiProyecto FAIL – Application already exists at path /MiProyecto C:\MiProyecto\MiProyecto\nbproject\build-impl.xml:594: The module has not been deployed. BUILD FAILED (total time: 9 seconds)

Esto no me deja correr la aplicación.

## Is there a way to improve performance here using No Exists?

I have three tables. One table has information on users, such as their name, bio, age etc. The primary key is the Id field alone. Second table shows people users follow (user_following) and the third table is to store relations with people who follow me (user_followers).

I want to find information on those users who have been removed from both the tables.

Users can have large IDs and hence the ID column is varchar with the lenght being max 25 characters as of now.

My query is this:

`select * FROM followers_info finfo LEFT JOIN user_followers uf ON uf.follower_id = finfo.follower_id LEFT JOIN user_following fing ON fing.follower_id = finfo.follower_id WHERE uf.follower_id IS NULL AND fing.follower_id IS NULL `

Attached is the explain results of this query:

Is there a way to improve the performance here?