Set Builder Calculator

Set Builder Notation Calculator

ℕ (Natural Numbers: {1, 2, 3, …}) ℤ (Integers: {…, -2, -1, 0, 1, 2, …}) ℚ (Rational Numbers) ℝ (Real Numbers)
Use `==` for equality, `%` for modulo. Supported operators: `==`, `!=`, `>`, `=`, `<=`, `+`, `-`, `*`, `/`, `%`, `AND`, `OR`, `NOT` (case-insensitive). For element listing, simple conditions work best.

Set Builder Notation:

{ x | x ∈ ℕ, x > 3 AND x < 10 }

Example Elements (if enumerable):

{ 4, 5, 6, 7, 8, 9 }

function calculateSet() { var variableSymbol = document.getElementById("variableSymbol").value.trim(); var universalSet = document.getElementById("universalSet").value; var conditionPredicate = document.getElementById("conditionPredicate").value.trim(); if (!variableSymbol) { alert("Please enter a variable symbol."); return; } if (!conditionPredicate) { alert("Please enter a condition/predicate."); return; } var universalSetSymbol = ""; var universalSetName = ""; switch (universalSet) { case "N": universalSetSymbol = "ℕ"; universalSetName = "Natural Numbers"; break; case "Z": universalSetSymbol = "ℤ"; universalSetName = "Integers"; break; case "Q": universalSetSymbol = "ℚ"; universalSetName = "Rational Numbers"; break; case "R": universalSetSymbol = "ℝ"; universalSetName = "Real Numbers"; break; } // Construct the set builder notation string var setNotation = "{ " + variableSymbol + " | " + variableSymbol + " ∈ " + universalSetSymbol + ", " + conditionPredicate + " }"; document.getElementById("setBuilderNotationOutput").innerHTML = setNotation; // — Attempt to list elements — var elements = []; var minRange, maxRange; var canListElements = true; var evalCondition = conditionPredicate.replace(/AND/gi, "&&").replace(/OR/gi, "||").replace(/NOT/gi, "!"); // Replace variable symbol with 'i' for evaluation var regex = new RegExp("\\b" + variableSymbol + "\\b", "g"); evalCondition = evalCondition.replace(regex, "i"); if (universalSet === "N") { minRange = 1; maxRange = 20; // Limit for practical listing } else if (universalSet === "Z") { minRange = -10; // Limit for practical listing maxRange = 10; } else { canListElements = false; document.getElementById("setElementsOutput").innerHTML = "Elements cannot be easily listed for infinite, dense sets like " + universalSetName + "."; } if (canListElements) { for (var i = minRange; i 0) { var ellipsis = ""; if (universalSet === "N" && maxRange -10 || maxRange < 10) && (elements[0] === minRange || elements[elements.length – 1] === maxRange)) { // If we hit limits for Z ellipsis = ", …"; } document.getElementById("setElementsOutput").innerHTML = "{ " + elements.join(", ") + ellipsis + " }"; } else { document.getElementById("setElementsOutput").innerHTML = "No elements found in the specified range (" + minRange + " to " + maxRange + ")."; } } } } // Run on initial load window.onload = calculateSet;

Understanding Set Builder Notation

Set builder notation is a powerful mathematical tool used to define a set by specifying the properties that its members must satisfy. Instead of listing every element (which is often impossible for infinite sets), it provides a rule or condition that determines membership.

The Structure of Set Builder Notation

The general form of set builder notation is:

{ variable | condition }

Or, more formally, including the universal set:

{ variable | variable ∈ Universal Set, condition }

Let's break down its components:

  • Variable: This is a placeholder symbol (e.g., x, n, y) that represents an arbitrary element of the set being defined.
  • The Vertical Bar (|) or Colon (:): This is read as "such that" or "where". It separates the variable from the condition.
  • Universal Set / Domain (∈ Universal Set): This specifies the larger set from which the elements are drawn. Common universal sets include:
    • (Natural Numbers): {1, 2, 3, …} (sometimes includes 0)
    • (Integers): {…, -2, -1, 0, 1, 2, …}
    • (Rational Numbers): Numbers that can be expressed as a fraction a/b where a, b are integers and b ≠ 0.
    • (Real Numbers): All rational and irrational numbers.
  • Condition / Predicate: This is the rule or property that the variable must satisfy to be a member of the set. It's a mathematical statement involving the variable.

How to Use the Set Builder Calculator

Our Set Builder Notation Calculator helps you construct and visualize sets defined by conditions:

  1. Variable Symbol: Enter the symbol you want to use for the elements of your set (e.g., x, n).
  2. Universal Set / Domain: Choose the larger set from which your elements will be drawn (Natural Numbers, Integers, Rational Numbers, or Real Numbers). This context is crucial for defining the set.
  3. Condition / Predicate: Input the mathematical condition that elements must satisfy. Use standard mathematical operators. For logical operations, use AND, OR, NOT (case-insensitive). For example:
    • x > 5
    • n % 2 == 0 (for even numbers)
    • y * y < 25
    • x > 0 AND x < 10
  4. Generate Set: Click the button to see the formal set builder notation and, for enumerable sets (Natural Numbers, Integers within a reasonable range), a list of example elements.

Examples of Set Builder Notation

Let's look at a few examples:

Example 1: Even Natural Numbers Less Than 10

  • Variable Symbol: n
  • Universal Set: (Natural Numbers)
  • Condition: n % 2 == 0 AND n < 10
  • Output Notation: { n | n ∈ ℕ, n % 2 == 0 AND n < 10 }
  • Output Elements: { 2, 4, 6, 8 }

Example 2: Integers Whose Square is Less Than or Equal to 9

  • Variable Symbol: x
  • Universal Set: (Integers)
  • Condition: x * x <= 9
  • Output Notation: { x | x ∈ ℤ, x * x <= 9 }
  • Output Elements: { -3, -2, -1, 0, 1, 2, 3 }

Example 3: Real Numbers Greater Than 0

  • Variable Symbol: y
  • Universal Set: (Real Numbers)
  • Condition: y > 0
  • Output Notation: { y | y ∈ ℝ, y > 0 }
  • Output Elements: Elements cannot be easily listed for infinite, dense sets like Real Numbers.

This calculator is a helpful tool for students and professionals alike to practice and understand the concise and powerful language of set theory.

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