Mathematics. Articles in English (et en français dans le futur).

Introducing Riemann-Stieltjes Integral

Introducing Riemann-Stieltjes Integral

Basic Facts of Semicontinuous Functions

Basic Facts of Semicontinuous Functions

An Introduction to Quotient Space

An Introduction to Quotient Space

关于《第三次忍受》

关于《第三次忍受》

The Big Three Pt. 3 - The Open Mapping Theorem (Banach Space)

The Big Three Pt. 3 - The Open Mapping Theorem (Banach Space)

Cauchy sequence in group theory

Cauchy sequence in group theory

A Brief Introduction to Fréchet Derivative

In this post we give a brief introduction too Fréchet derivatives, a generalisation of derivatives in Banach spaces, and deduce *elementary* properties.
A Brief Introduction to Fréchet Derivative

An elementary introduction to profinite groups

An elementary introduction to profinite groups

线性ODE(四)——常系数高阶线性微分方程的普遍解法

线性ODE(四)——常系数高阶线性微分方程的普遍解法

A continuous function is 'mostly' nowhere differentiable

A continuous function is 'mostly' nowhere differentiable