"Elementary Calculus: An Infinitesimal Approach" is a textbook authored by H. Edward Verhulst. It presents calculus using the concept of infinitesimals, which are quantities that are closer to zero than any standard real number yet are not zero themselves. This approach is different from the traditional epsilon-delta definitions commonly used in calculus classes. The book aims to provide a more intuitive understanding of calculus concepts by employing infinitesimals in the explanation of limits, derivatives, and integrals.

A quasi-continuous function is a type of function that is continuous on a dense subset of its domain.

Tensor calculus is a mathematical framework that extends the concepts of calculus to tensors, which are geometric entities that describe linear relationships between vectors, scalars, and other tensors. Tensors can be thought of as multi-dimensional arrays that generalize scalars (zero-order tensors), vectors (first-order tensors), and matrices (second-order tensors) to higher dimensions.

Analytic number theory is a branch of mathematics that uses tools and techniques from mathematical analysis to solve problems about integers, particularly concerning the distribution of prime numbers. It is a rich field that combines elements of number theory with methods from analysis, particularly infinite series, functions, and complex analysis.

A Blaschke product is a specific type of function in complex analysis that is defined as a product of terms related to the holomorphic function behavior on the unit disk. Specifically, a Blaschke product is constructed using zeros that lie inside the unit disk. It is a powerful tool in the study of operator theory and function theory on the unit disk. Formally, if \(\{a_n\}\) is a sequence of points inside the unit disk (i.e.

The Cauchy-Riemann equations are a set of two partial differential equations that are fundamental in the field of complex analysis. They provide necessary and sufficient conditions for a function to be analytic (holomorphic) in a domain of the complex plane.

The Inverse Laplace Transform is a mathematical operation used to convert a function in the Laplace domain (typically expressed as \( F(s) \), where \( s \) is a complex frequency variable) back to its original time-domain function \( f(t) \). This is particularly useful in solving differential equations, control theory, and systems analysis.

The logarithmic derivative of a function is a useful concept in calculus, particularly in the context of growth rates and relative changes. For a differentiable function \( f(x) \), the logarithmic derivative is defined as the derivative of the natural logarithm of the function.

A Nevanlinna function is a special type of analytic function that is used in the study of Nevanlinna theory, which is a branch of complex analysis focusing on value distribution theory. This theory, developed by the Finnish mathematician Rolf Nevanlinna in the early 20th century, deals with the behavior of meromorphic functions and their growth properties.

A power series is a type of infinite series of the form: \[ f(x) = \sum_{n=0}^{\infty} a_n (x - c)^n \] where \( a_n \) are the coefficients of the series, \( c \) is a constant (often referred to as the center of the series), and \( x \) is a variable.

Weihrauch reducibility is a concept from the field of computability theory and reverse mathematics. It arises in the study of effective functionals, particularly in the context of understanding the complexity of mathematical problems and their solutions when framed in terms of algorithmic processes. In basic terms, Weihrauch reducibility provides a way to compare the computational strength of different problems or functionals.

An **inclusion map** is a concept used in various areas of mathematics, especially in topology and algebra. Generally, it refers to a function that "includes" one structure within another. Here are two common contexts where the term is used: 1. **Topology**: In topology, an inclusion map typically refers to the function that includes one topological space into another.

Bijection, injection, and surjection are concepts from set theory and mathematics that describe different types of functions or mappings between sets. Here’s a brief explanation of each: ### 1. Injection (One-to-One Function) A function \( f: A \to B \) is called an **injection** (or one-to-one function) if it maps distinct elements from set \( A \) to distinct elements in set \( B \).

Homeomorphism is a concept in topology, a branch of mathematics that studies the properties of space that are preserved under continuous transformations. Specifically, a homeomorphism is a continuous function between two topological spaces that has a continuous inverse. Formally, let \( X \) and \( Y \) be topological spaces.

Boris Levitan could refer to multiple individuals, but one notable person by that name is a Russian-American mathematician known for his work in the field of mathematics, particularly in the areas of functional analysis and differential equations. However, without more context, it's challenging to provide specific information about a particular Boris Levitan you might be referring to.

Oblique reflection refers to the reflection of waves, such as light, sound, or other types of waves, off a surface at an angle that is not perpendicular to that surface. In optics, when light rays strike a reflective surface at an angle other than 90 degrees, they undergo oblique reflection.

A ridge function is a specific type of function that can be expressed as a composition of a function of a single variable and a linear combination of its inputs.