Hamming Code and Hadamard Code || @ CMU || Lecture 11c of CS Theory Toolkit

Hamming Code and Hadamard Code || @ CMU || Lecture 11c of CS Theory Toolkit

🎙 Ryan O'Donnell 👥 14K 📅 April 7, 2020 ⏱ 21 min 👁 4K 📄 lecture 🧭 2026-08-17
Available in: English (current) Français

Keywords

Hamming codeHadamard codelinear codeparity check matrixminimum distance

Summary

This lecture, part of a graduate course on theoretical computer science at Carnegie Mellon University, introduces two fundamental linear error-correcting codes: the Hamming code and the Hadamard code. The Hamming code is defined by a parity-check matrix whose columns are all non-zero binary vectors of a given length. It achieves a high rate (close to 1) but has a minimum distance of only 3, allowing correction of at most one error. The lecture highlights its perfect code property, meaning Hamming balls of radius 1 around codewords partition the entire space. The Hadamard code is the dual of the Hamming code (with a minor modification) and is defined by evaluating all linear polynomials over F2. It has a terrible rate (exponential blow-up) but an excellent minimum distance of n/2, where n is the block length. The lecture provides three proofs of this distance property, including via the Hadamard matrix and the Schwartz-Zippel lemma. The presentation emphasizes the trade-off between rate and distance, setting the stage for more advanced codes that achieve both good properties.

173 words

Critical Evaluation

Value of the Information & Strength of the Argument

The lecture provides a clear and rigorous introduction to two classic codes, emphasizing their dual nature and the trade-off between rate and distance. The argumentation is solid: the Hamming code’s minimum distance is derived from the properties of its parity-check matrix, and the Hadamard code’s distance is proven via multiple methods, including the Hadamard matrix and the Schwartz-Zippel lemma. The presentation is well-structured, building on previous lectures on linear algebra and polynomials. The value lies in the deep understanding of these fundamental codes and their properties, which are essential for further study in coding theory and theoretical computer science.

Scientific Rigor, Source Quality, Title Accuracy

The lecture is scientifically rigorous, with precise definitions and proofs. The sources are standard textbooks on coding theory, as mentioned in the description (MacWilliams & Sloane, van Lint, Roth, Guruswami et al.), though not explicitly cited during the lecture. The title accurately reflects the content, focusing on the Hamming and Hadamard codes. The lecture is part of a well-established graduate course, and the instructor is a recognized expert, enhancing credibility. No comments were provided for analysis.

190 words

Title / Content Match

The title accurately reflects the content: the lecture covers the Hamming and Hadamard codes, both fundamental in coding theory.

Quality & Reliability

8/10

Lecture by a recognized expert in theoretical computer science, part of a graduate course at Carnegie Mellon University. The content is mathematically rigorous, with clear definitions and proofs. However, it is a lecture, not peer-reviewed, and relies on standard textbook material.

Key Moments

Cited Sources

Concurring Sources

  • MacWilliams & Sloane, The Theory of Error-Correcting Codes — Standard reference on coding theory, mentioned in the description.
  • van Lint, Introduction to Coding Theory — Classic textbook on coding theory, mentioned in the description.
  • Guruswami, Rudra, Sudan, Essential Coding Theory — Modern textbook on coding theory, mentioned in the description.

Contribution & Novelties

This lecture provides a clear and rigorous exposition of two fundamental codes, highlighting their dual nature and the trade-off between rate and distance. It offers multiple proofs for the Hadamard code’s distance, including via the Hadamard matrix and the Schwartz-Zippel lemma, which is pedagogically valuable. The lecture also introduces the concept of perfect codes and sets the stage for more advanced codes like Reed-Solomon and LDPC codes.

Pour aller plus loin :

123 words

Radar Profile

The radar profile shows high scores in quality of information, technical level, and reliability, with slightly lower but still strong scores in quantity of information. This indicates a dense, rigorous lecture that is highly reliable but may be challenging for beginners due to its technical depth.

Reliability 8/10