डबल-स्ट्रक कैपिटल जेड ℤ

The set of integers ℤ = {…, -2, -1, 0, 1, 2, ...} consists of the natural numbers (positive integers), their negative counterparts, and zero. The term ‘integer’ comes from the German word ‘Zahl,’ meaning ‘number.’ The set ℤ is countable (equivalent in cardinality to the set of natural numbers ℕ).

The sets ℕ , ℤ , ℚ , ℝ , ℂ are often written in bold font (for example, in the works of Nicolas Bourbaki) or as double-struck letters on blackboards and manuscripts. American mathematicians introduced the usage of double-struck font in printed texts, and it became popularized with the famous textbook on complex analysis by Gunning and Rossi, published in 1965.

संकेत ‘डबल-स्ट्रक कैपिटल जेड’ ‘अक्षर चिह्न’ उपखंड में शामिल है, जो ‘पत्र-जैसे प्रतीक’ खंड का हिस्सा है, और यह Unicode संस्करण 1.1 के भाग के रूप में 1993 में स्वीकृत हुआ था।