This site is devoted to mathematics and its applications. Created and run by Peter Saveliev.

# Peter Saveliev

Hello! My name is Peter Saveliev (rhymes with “leave”). I am a professor of mathematics at Marshall University, Huntington WV, USA.

My current projects are these two books:

*Topology Illustrated*, published in 2016*Calculus Illustrated. Volume 1 Precalculus, published in 2019**Calculus Illustrated. Volume 2 Differential Calculus, published in 2020**Calculus Illustrated. Volume 3 Integral Calculus, published in 2020**How Swords Cut*, published in 2020*Linear Algebra Illustrated*, published in 2020*Calculus Illustrated. Volume 4 Calculus in Higher Dimensions, to be published in 2021**Calculus Illustrated. Volume 5 Differential Equations, to be published in 2021*

The calculus series includes parts of *Discrete Calculus*, which is based on a simple idea:
$$\lim_{\Delta x\to 0}\left( \begin{array}{cc}\text{ discrete }\\ \text{ calculus }\end{array} \right)= \text{ calculus }$$

They are sold on Amazon:

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I have been involved in research in algebraic topology and several other fields but nowadays I think this is a pointless activity. My non-academic projects have been: digital image analysis, automated fingerprint identification, and image matching for missile navigation/guidance.

- Once upon a time, I took a better look at the poster of
*Drawing Hands*by Escher hanging in my office and realized that what is shown isn't symmetric! To fix the problem I made my own picture called*Painting Hands*:

Such a symmetry is supposed to be an involution of the $3$-space, $A^2=I$; therefore, its diagonalized matrix has only $\pm 1$ on the diagonal. These are the three cases:

- (a) One $-1$: mirror symmetry, then pen draws pen. No!
- (b) Two $-1$'s: $180$ degrees rotation, the we have two right (or two left) hands. No!
- (c) Three $-1$'s: central symmetry. Yes!

- - Why is discrete calculus better than infinitesimal calculus? - Why? - Because it can be integer-valued! - And? - And the integer-valued calculus can detect if the space is non-orientable! Read Integer-valued calculus, an essay that makes a case for discrete calculus by appealing to topology and physics.

- - The political “spectrum” might be a circle! - So? - Then there can be no fair decision-making system! Read The political spectrum is a circle, an essay based on the very last section of the topology book.