---
title: "Einstein summation expression mathematical notation"
description: "Einstein summation expression is a recurring research-paper notation family. Specifies tensor alignment, multiplication, contraction, and output axes…"
canonical_url: "https://fanout.sh/labs/math-decoder/symbol/einsum"
md_url: "https://fanout.sh/labs/math-decoder/symbol/einsum.md"
last_updated: "2026-08-09"
access: "public"
---

# Einstein summation expression mathematical notation

Einstein summation expression is a recurring research-paper notation family. Specifies tensor alignment, multiplication, contraction, and output axes…

## Public overview

Einstein summation expression is a recurring research-paper notation family. Specifies tensor alignment, multiplication, contraction, and output axes through named index labels.

Einstein summation expression: Specifies tensor alignment, multiplication, contraction, and output axes through named index labels. Example: Contract the shared k axis to multiply matrices.

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