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Tom Collinge

Johannesburg, Gauteng, South Africa

Retired IT project manager with atrophied maths degree.

Married, +2, ++5

Interests: family, bridge, gym, cooking, music, maths

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Top Questions
12 votes

Basis for Tensor Product of Infinite Dimensional Vector Spaces

vector-spaces tensor-products multilinear-algebra asked Mar 6, 2015 at 8:59
math.stackexchange.com

12 votes

Topology: reference for "Great Wheel of Compactness"

general-topology reference-request soft-question compactness asked Dec 29, 2015 at 12:28
math.stackexchange.com

11 votes

What's an Isomorphism?

abstract-algebra logic category-theory asked Feb 11, 2016 at 11:34
math.stackexchange.com

10 votes

Why is Multiplicative Notation Used for Groups (Instead of Additive)?

group-theory notation asked Jan 29, 2015 at 14:23
math.stackexchange.com

10 votes

Confused about Domain of Unbounded Operators (Hilbert Spaces)

hilbert-spaces unbounded-operators asked Jul 6, 2016 at 11:58
math.stackexchange.com

8 votes

Confused about Euclidean Norm

vector-spaces norm asked Oct 14, 2015 at 9:17
math.stackexchange.com

7 votes

What is the Relationship between a Closed Map and a Closed Linear Operator?

general-topology banach-spaces asked Aug 14, 2016 at 18:48
math.stackexchange.com

7 votes

Definition of Essentially Self Adjoint Operators

functional-analysis operator-theory hilbert-spaces adjoint asked Apr 10, 2017 at 8:51
math.stackexchange.com

7 votes

Equivalence of Continuous Monotonic Functions $[0, 1] \to [0, 1]$

real-analysis general-topology alternative-proof curves asked Aug 12, 2019 at 9:17
math.stackexchange.com

6 votes

What is the Orientation of the "All-Sky" Projection?

astronomy coordinate-systems cmb asked Nov 18, 2016 at 8:07
physics.stackexchange.com

1 2

Top Answers
29
How to distinguish between walking on a sphere and walking on a torus?
math.stackexchange.com

11
Linear Algebra, Vector Space: how to find intersection of two subspaces?
math.stackexchange.com

11
Let $f(x)=ax^2+bx+c$ where $a,b,c$ are real numbers. Suppose $f(-1),f(0),f(1) \in [-1,1]$. Prove that $|f(x)|\le \frac{3}{2}$ for all $x \in [-1,1]$.
math.stackexchange.com

10
no. of real roots of the equation $ 1+\frac{x}{1}+\frac{x^2}{2}+\frac{x^3}{3}+............+\frac{x^7}{7} = 0$
math.stackexchange.com

10
Is a set without limit points necessarily closed?
math.stackexchange.com

9
Why does the Cauchy-Schwarz Inequality even have a name?
math.stackexchange.com

8
Axiom of Extensionality - Why not called equality?
math.stackexchange.com

8
What's the difference between tuples and sequences?
math.stackexchange.com

8
Proving bijection is an equivalence relation
math.stackexchange.com

7
Does $f(f(x)) = x \Rightarrow f$ is bijective apply?
math.stackexchange.com

7
How to prove invariance of dot-product to rotation of coordinate system
math.stackexchange.com

7
Could you see what you are typing in a Teletype?
retrocomputing.stackexchange.com

6
Induction: Prove that it is possible to seat people in a circle so that everyone sits beside a friend
math.stackexchange.com

6
Why is the absolute sign needed in the definition of a bounded function
math.stackexchange.com

6
what is the difference between ${10 \choose 2}$ and ${10 \choose 1}\times{9 \choose 1}$?
math.stackexchange.com

6
dom(A) is a Banach space w.r.t. the Graph-norm
math.stackexchange.com

5
Strong Induction Base Case
math.stackexchange.com

5
How to show that this real function is not periodic?
math.stackexchange.com

5
What is the truth table for demorgan's law?
math.stackexchange.com

5
A finite set has no limit points
math.stackexchange.com

5
From finite union to infinite union
math.stackexchange.com

5
How were bugs reported for compilers that were shipped on floppy disks?
retrocomputing.stackexchange.com

5
Measurability of an a.e. pointwise limit of measurable functions.
math.stackexchange.com