# The-erinaceous-one

Joined 22 July 2020
Babel user information
en-N This user has a native understanding of English.
es-1 Este usuario tiene un conocimiento básico del español.
 $\,\,e^{i\pi }$ This user is a member ofWikiProject Mathematics This user is a member ofWikiProject Ontology This user is a member ofWikiProject Properties.
Users by language

My name is Paul Wintz, AKA The Erinaceous One 🦔. I am a PhD student at the University of California, Santa Cruz (Q1047293), where I study control theory (Q6501221) in the Department of Applied Mathematics.

Where to find me accross the internet:

## To-do List

The following are tasks that I am planning to work on.

1. Create "identity element" and "inverse operation."
2. Add explanation of second-order metaclass (Q24017465) (and similar items) on its talk page. (Maybe track down the "true" documentation for ontology and link it there).
3. Add a more complete example to defining formula page with demonstrates how to use "calculated from" and "in defining formula"
4. Add more "generalization of" statements to mathematical items
5. Create "mathematically equivalent to" property?
6. Create "has conclusion" property for proof items?
7. Integrate Wikidata:List of properties/mathematics into the mathematics project page.
8. Clarify the difference between numerical method has quality A-stability and Euler backward method has quality A-stability.
9. Why is trio (Q281643) instance of musical term? Isn't that language dependent?
10. What the relationship between signed curvature and curvature?
11. Clean up the instances of mathematical object. In particular, shape (Q207961) has many subclasses that should not be mathematical objects.
12. Develop Template:Instance Criteria

## Properties and Templates I Find Useful

Qualifiers:

### Templates

To talk about templates, use the template {{Tl}}

How do we represent that instances of dimension of a vector space (Q929302) will be integer values?

## Important Math Items

The following are classes of mathematical objects that I patrol occasionally to make sure the ontology of their instances and subclasses are correct.

I also have some expertise in the following categories, so I try to develop and maintian them:

### Frequently misused

There are several mathematics terms that are easily confused with everyday terms, so I periodically check them for misuse.

## Property Proposals

### Properties I'm considering proposing:

#### Other

• "Belmann equation" "necessary condition for" "solution to dynamic program"
• "solution to dynamic program" "has necessary condition" "Bellman equation"
• " " "suffcicient condition for" " "
• " " "is suffcicient condition" " "
• "control signal" produced by controller
• "is porportional to"
• negation truth table <truth table>
• R^2 cartesian product of "items listed as qualifiers" / of R / of R
• R^2 direct product of "items listed as qualifiers" / of $\{(x,y)\mid x=0\}$  / of $\{(x,y)\mid y=0\}$

#### qualities for this type

• Human "qualities for this type" male, female
• iterative numerical method "qualities for this type" L-stable, A-stable, zero-stable,

#### Instances all have quality

• Runge-Kutta method "All instances have quality" Butcher tableau
• linear functional "All instances have quality" "Listed as qualifiers" / codomain field of scalars

#### Units

ISQ dimension (P4020)
${\mathsf {M}}{\mathsf {T}}^{-2}$
 SI mass unit power 1
 SI time unit power -2
0 references

### Failed Proposals Worth Revisting

Wikidata:Property proposal/Implies (necessary condition) (Also includes logical/axiomatic system)

## SPARQL Queries

### Runge-Kutta methods

Show all the Runge-Kutta methods sorted by the number of stages.

select distinct
?method
?methodLabel
?formula
?Butcher
?stages
?orderOfConvergence
where {
?method wdt:P31*/wdt:P279* wd:Q725944.
optional{?method wdt:P2534 ?formula .}
optional{?method wdt:P8558 ?Butcher.}
optional{?method p:P1552 [ps:P1552 wd:Q97672364; pq:P1114 ?stages].}
optional{?method p:P1552 [ps:P1552 wd:Q97940482; pq:P1181 ?orderOfConvergence].}
SERVICE wikibase:label { bd:serviceParam wikibase:language "[AUTO_LANGUAGE],en". }
} ORDER BY (!bound(?stages)) ASC(?stages) (!bound(?orderOfConvergence)) ASC(?orderOfConvergence)


### Linear Multistep Methods

Show all linear multistep methods sorted by the number of steps.

select distinct
?method
?methodLabel
?formula
?steps
?orderOfConvergence
where {
?method wdt:P31*/wdt:P279* wd:Q1462003.
optional{?method wdt:P2534 ?formula .}
optional{?method p:P1552 [ps:P1552 wd:Q98293869; pq:P1114 ?steps].}
optional{?method p:P1552 [ps:P1552 wd:Q97940482; pq:P1181 ?orderOfConvergence].}
SERVICE wikibase:label { bd:serviceParam wikibase:language "[AUTO_LANGUAGE],en". }
} ORDER BY (!bound(?steps)) ASC(?steps) ASC(?orderOfConvergence)


### Defining Formulas

select
?quantity
(sample(?label) as ?label)
(sample(?desc) as ?desc)
(sample(?symbol) as ?symbol)
(sample(?formula) as ?formula)
(
strdt(
concat(
"<", "math><mtable columnalign=left>",
group_concat(?symbolAndLabel),
"</mtable>[/itex]"
),
<http://www.w3.org/1998/Math/MathML>
) as ?otherSymbols
)
where {
?quantity wdt:P279+ wd:Q71550118 .
optional { ?quantity rdfs:label ?label . filter (lang(?label) = "en") }
optional { ?quantity schema:description ?desc . filter (lang(?desc) = "en") }
?quantity wdt:P2534 ?formula .
?quantity wdt:P7235 ?symbol .
{
select distinct * where {
?quantity p:P4934 [ pq:P7235 ?otherSymbol ; ps:P4934 / rdfs:label ?otherLabel ] .
filter (lang(?otherLabel) = "en")
bind (
concat(
"<mrow>",
str(?otherSymbol), "<mtext>", ": ", ?otherLabel, "</mtext>",
"</mrow>"
) as ?symbolAndLabel
)
}
}
} group by ?quantity ?formula


### Number classification

The following might be useful information on the mathematics project page.

Important Number Items
Natural Numbers Integers Rationals Real Numbers
number (Q11563) natural number (Q21199) integer (Q12503) rational number (Q1244890) real number (Q12916)
set of numbers (Q3054943) set of natural numbers (Q28777634) set of integers (Q47007735) set of rational numbers (Q47005650) set of real numbers (Q26851380)
type of number (Q47460393) type of natural numbers (Q77359186) type of integer (Q77358734) ?? ??