What is known about the common knowledge of mathematicians outside their field?

When giving a talk or writing a paper intended for non-specialist (i.e., mathematicians not specializing in the topic being discussed), the question inevitably occurs of what one can assume to be “common knowledge”. Rather than trying to guess (e.g., I assume that almost all mathematicians know what a vector space over a field and what the Lebesgue measure are), it would probably be better to determine this experimentally. Have any surveys been conducted in order to answer this question?

Roughly which set of mathematical definitions and facts are known to a proportion at least $ p$ of working mathematicians?

(Here, $ \frac{1}{2}\leq p<1$ is some fixed but specified quantity. Of course, a survey like this would in fact measure how well-known various notions and theorems are, so would give results for a variety of different $ p$ . Also of course, this depends on some definition of what a “working mathematician” is, I’m assuming self-reporting as such, but I don’t think the details are too important; even a survey limited to a particular country or membership to a particular mathematical society would be something.)

It seems to me that this would be interesting both mathematically (see above) and sociologically. More refined results indicating how results vary per country, per age group, or per specialty, would of course be of value, but any survey along these lines would interest me.

I tried Googling various terms to no avail, so I’m inclined to think that no such survey was ever conducted, but maybe I missed something.

Shortest common supersequence with Genetic Algorithm

I’m trying to solve the shortest common supersequence with Genetic Algorithm. I found it a little bit hard to reduce the size of the chromosomes in each generation.

I know that the maximum size of the chromosome is the total length of the strings. Even if we create a “naive” genetic algorithm: Totally random strings (with different length) as initial population, mutation that replace a character, fitness that return how much strings that chromosome contains etc. How the crossover can reduce the size of the chromosome length? If we choose n-points crossover, the length of the children cannot be smaller than the shorter parent.

So how genetic algorithm can solve such problems that need the shortest chromosome length? How crossover can reduce the chromosome length?

Is it a common practice to give a user an unmodifiable password?

I created an online account on a website, they do not ask me for a password but just an email address, then, after acknowledging “terms of service” I was already logged-in.

Then I received an email with a password (ten characters like automatically generated password) and this advice:

Please note that passwords are case sensitive. [website name] handles sensitive information on behalf of some its members and other organisations. To help protect your data, we automatically assign secure passwords. To maintain this security, you cannot change your password and we have no means of retrieving lost passwords.

This was something I have never seen before and leave me with a lot of doubts about the trustworthiness of the website. I was expecting at least the capability to change the password.

Are there common problems between rounting and mat-dialogs in Angular?

What I wanted to do was to open a mat-dialog by clicking on an icon. This mat-dialog is a split panel that has to the left side buttons that can be clicked and to the right side a content space where other components are supposed to be loaded on click on the specific button. Now, I followed the guidelines of the original documentation for routing on https://angular.io/guide/router , but when I clicked the first icon to open the dialog, it’s style was changed and it didn’t open in form of a dialog anymore. Now I figured I could just keep the dialog style by changing the url within the method of calling the dialog like this

dialogRef.afterOpened().subscribe(result => {       this.router.navigate(['/dialog']);     });    dialogRef.afterClosed().subscribe(result => {      this.router.navigate(['']);     }); 

Like this the url changed with opening anf closing the dialog the way I wanted. But I’ve got another routing-module with another component, which is working perfectly fine, before opening the dialog,but does not work anymore afterwards. And now the loading of the component via routing and using <router-outlet> in the html tag does not work either. Now, my question is if there are some general problems with mat-dialog and routing that I might solve by using a different way? Is it necassary to code a custom dialog (not using mat-dialog)? I had everything working fine before with a service, though I thought changing the url and opening the components by navigation would be a lot less code and a nicer solution.

Hopefully, someone can explain this problem to me and what is actually happening. I might provide more general code, but like I said I pretty much followed the official documentation. Thanks in advance!

Common Mac issues

Most of the users are getting such kind of similar issues on their Mac based system. They just need an actual solution to resolve their issues. They will definitely get an appropriate solution from error code 0x80070057 that will guide to recover their troubles easily.

How can I include common strings (regexes) in several projects written in different languages?

I have a simple Go library (~300 lines, mostly type declarations and nice methods and compatibility methods for gomobile etc., also pretty-printing scripts). The heart of the whole project are two regexes, placed in a separate file in my Go repository.

Now I want to port that simple library to Python, Java (Android), maybe Javascript. I want the regexes to rest in a single Git repository (maybe even the Golang one).

What is the best way to include the regexes at compile/build time as string constants? In case of Golang, it seems that the only way is to use go generate, which generates source code files and could include those regexes from a plain text file. So I decided to make a separate Go source code file for easy parsing by other build tools in case of Python, Java, Javascript. I would appreciate any advice how to do it efficiently that way. I could also make a separate repository for two regexes and use git submodules (or even treat it as a sepratate Go package in Go project).

But I’ve lost my hope for a pretty solution, and that’s why I’m asking here and not on SO; how do you solve such problems? The simplest way would be to manually “cherry-pick” commits from each repository, setting author field manually.

Is it common for the L5R clans to have territories far from their main land?

In the introduction to the Naishou Province supplement, it is explained how a number of clans want to control the province.

The localization of the Province is intentionally not mentioned, but I would like to place it somewhere on the Rokugan map for a campaign.

However, I want it to make sense given the clans who want the control of the province. But I am not sure if it makes sense for, say, the Clab cran (who is located in the south of Rokugan) to try to acquire a province that would be in the north (just an example, I’m still not sure about where to put it).

Thus my question: Is it common for clans to own territories far from their main land? If it’s rare, which clans would be likely to do that?

WebAPI Versioning practice – Common version to all controllers

I am using Microsoft.AspNet.WebApi.Versioning for versioning my WebAPI project.

I already used version through the header with CustomControllerSelector class. After learning this package, I am changing my application using this package.

I maintained separate API versions for different controllers. I mean, I have Orders controller and purchase controller. Here orders controller may be in version 3 and purchase controllers may be in version 2.

I don’t know the common version is the best practice. Currently, I am planning to update it as common version so that if any changes happened in any version, all APIs version will be updated to the latest one. I got this idea when learning about ‘Version Interleaving’ concept in the package. Here I thinking that without any reason, I need to upgrade my version if any version changes happened for other controllers.

Please advice which one is the best practice.

  1. Separate version for separate controller/function
  2. Common version for every controller and update to the new version