Questions tagged [singularity]

This tag is for questions relating to singularity, which is a point where a mathematical concept is not defined or well behaved, such as boundedness, differentiability, continuity. In general, because a function behaves in an anomalous manner at singular points, singularities must be treated separately when analyzing the function, or mathematical model, in which they appear.

A singularity or, singular point is a point at which a function, equation, surface, etc., becomes degenerate or just diverges towards infinity.

The word singular means something that is extraordinary, unique, and strange. When we talk about singularity in mathematics, we usually refer to the uniqueness of mathematical objects. In particular, singularities refer to the points where the mathematical objects are not well-behaved i.e. we can’t define them for those points.

Why we study about singularity:

The study of singularity is extremely important in many different fields. We employ complex mathematical formulations when we build physical structures and surfaces. These formulations are governed by the underlying functions, and if we don’t understand the singularities of those functions, the physical structure will collapse. Apart from this, they are used in particle physics, quantum mechanics, relativity, study of deformable surfaces, light patterns, and many more fields. We construct so many devices based on these physical phenomena, and all of them are critically dependent on their corresponding singularities

Singularity in Complex Analysis:

Singularities are extremely important in complex analysis, as they characterize the possible behaviors of analytic functions. Complex analysis refers to analysis of functions whose domain and range can include the complex number set. Complex singularities are basically points in the domain of a function where it fails to be analytic.

Classification:

Singularities can be non-isolated or isolated. Non-isolated singularities usually arise due to our own definitions of boundaries, like if we choose to define the function only within a certain limit. They are not very interesting to us because we know exactly why they occur. Isolated singularities, on the other hand, arise due the inherent nature of the functions. They refer to those isolated points where the function behavior is not defined. Isolated singularities may be classified as removable singularities, poles, essential singularities, and logarithmic singularities.

References:

https://en.wikipedia.org/wiki/Singularity_(mathematics)

http://mathworld.wolfram.com/Singularity.html

https://en.wikipedia.org/wiki/Singularity

1025 questions
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Types of singularities, why is this an essential singularity

I'm learning about different types of singularities: 1) removable singularities. 2) poles. 3) essential singularities. I think I understand 1 and 2 but I don't really get the 3rd one, could someone please explain me? 1) For a removable…
Amaluena
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Are holes in functions real?

One way to create a function with a hole is multiplying and dividing it by x, like this: $f(x) = 1$ $g(x) = \frac{x}{x}$ This creates a so-called "removable singularity" at $x=0$. At school I was taught not to remove such singularities, so I wonder…
potato
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Singularities classification

2 unsolved questions: Prove that all the singular points of rational function $f(z)=\frac{P_1(z)}{P_2(z)}$, where $P_{1,2}$ are polynomials, are either removable singularities or poles. Consider function $f(z)$, and it's derivative $f'(z)$. Given…
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Can singularities appear on cartesian planes as vertical lines?

The equation $y(x-1)=x^2-1$ can be graphed on Cartesian plane by inserting values in for $y$ and then solving for $x$ For example, if $y=3$ then: $3(x-1)=x^2-1$ $3x-3=x^2-1$ $3x=x^2+2$ $0=x^2-3x+2$ $0=(x-2)(x+1)$ Thus $x=1$ or $2$ and so…
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Classifying of isolated singularities

I want to find out, which singualrities $f(z)=\frac{z}{e^z+1}$ have? $e^z+1=0 \Leftrightarrow z_k=(2k+1)i \pi $ But how can I find out, of which type these singualrities are?
Sven
  • 149
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resolution of singularity of segre variety

I read a book related to determinantal variety. In the book, I studied fact that $M_{k-1}$is singular locus of $M_{k}$, (here $M_k$ means $m*n$ matrices with rank at most $k$) my question is : I know that $M_1$ is segre variety. then what…
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Essential singolarity

I'm trying to solve an exercise about the classification of singolarity of a function. $f(z)=\frac{e^{iz+1}-1}{(z^2+1)^2}$ I have found two poles. A first order pole in $i$ and a second order pole in $-i$. There should also be an essential…