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3 votes
2 answers
125 views

Creating larger structures from smaller ones without an explicit construction

I'm asking this question as a replacement for my previous one, which I admit isn't clear, and which I am voting to close. Hopefully I'll be clearer now. Admittedly, I'm not sure if this question ...
jvf's user avatar
  • 585
1 vote
0 answers
178 views

When mathematicians say "true" do they mean "true in all models"?

According to the comments to this question, Truth is ordinarily defined by reference to models. If so, even axioms and theorems are not true without reference to a model. However, when ...
MathMan's user avatar
  • 103
-1 votes
1 answer
168 views

What are the differences between equality, equations and identities? [duplicate]

What are the differences between the followings: Identity $$ \sin^2(\alpha) + \cos^2(\alpha) = 1 $$ Equation $$ 4x = 16 $$ Equality - $x,y$ are mathematical objects. $$ x = y $$ All of the three ...
mawaior's user avatar
  • 375
1 vote
0 answers
56 views

What makes one proof different from another one? [duplicate]

There are around 370 different ways to prove the Pythagorean Theorem, but what does that exactly mean? For instance, if your proof states that $x^2+y^2=z^2$, I could construct a different one by ...
nuuusxd's user avatar
  • 33
0 votes
0 answers
66 views

Using set-builder notation in an unusual way for more concise expressions in a definition. Good style?

What do you think about the following usage of the set-builder notation $\{ x \mid P(x) \}$? Let $Y = \{ p_1, \ldots, p_n \}$ be $n$ objects and $A,B$ subsets of $Y$. Define a function from $\{1,\...
StefanH's user avatar
  • 18.2k
-3 votes
1 answer
307 views

Why are inference rules necessary?

It has been stated, both on this site and elsewhere, that without inference rules, a theory can only prove its own axioms. I don't understand how, though, and will try to show derivation without ...
user110391's user avatar
  • 1,129
1 vote
0 answers
64 views

Terminology for placeholder for elements of a set

Let $\mathbb{X}=\{1,2,3,4,5\}$ be a set and $x$ be an element of the set. Then 1 is also an element of the set. We say that $x$ is a "variable". I am searching for a word that conveys the ...
Make42's user avatar
  • 1,131
0 votes
1 answer
119 views

Analytic works versus synthetic works in mathematical research

With the purpose to clarify my ideas about terminology I would like to ask in Mathematics Stack Exchange what is the difference of two verbal expressions: when a professional mathematician understands ...
user759001's user avatar
1 vote
0 answers
63 views

Is the length of a line a property of that line, or is it its own mathematical object?

I'm trying to understand the nature of mathematical objects. As far as I understand it, mathematics studies these objects. Geometric shapes are one kind of such object, including 1D shapes, namely ...
Neb's user avatar
  • 11
1 vote
1 answer
67 views

Are there operations that can't be defined using a rule, and if they exist what is their significance?

Wikipedia:Operations(mathematics) In mathematics, an operation is a function which takes zero or more input values (called operands) to a well-defined output value What I took away from this fact ...
lmn32's user avatar
  • 99
1 vote
1 answer
328 views

What is the term for a value that is directly dependent upon other values?

Say you have variables A and B, both of which express a certain quantity. Now let's say you have X, which equals the sum of A and B. For example, A = 10, B = 5, and X = 15 because 10 + 5 = 15. The ...
user2901512's user avatar
  • 2,100
1 vote
0 answers
57 views

What is this process/action called in English?

it is a fairly generate question regarding a terminology. People without science or engineering discipline makes an unfounded claim X, but people with such discipline start with proven facts A, B, C, ...
AussieDude's user avatar
32 votes
7 answers
5k views

Why do we call complex numbers “numbers” but we don’t consider 2-vectors numbers?

We refer to complex numbers as numbers. However we refer to vectors as arrays of numbers. There doesn’t seem to be anything that makes one more numeric than the other. Is this just a quirk of history ...
Q the Platypus's user avatar
3 votes
3 answers
134 views

How do we say that two logically equivalent definitions are not semantically equivalent?

This is a question of terminology (and also relates to philosophy). Very often we have a certain term, such as "differentiable function", and then we have a definition: (1) def. A differentiable ...
user56834's user avatar
  • 13.4k
-5 votes
2 answers
215 views

In "10 grams of salt", is the unit "grams"?

The gram is a unit of mass, so "10 grams" has "grams" as the unit. "10 pounds" uses a different unit. So what is the "salt" in "10 grams of salt", if not a unit? In other words, what is the ...
mgiuffrida's user avatar

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