Discrete Math Logic Calculator

Build complete truth tables for symbolic logic statements. Compare formulas, test validity, and export results. Study discrete math proofs with clear reliable step summaries.

Calculator Inputs

Example: ((p -> q) AND p) -> q
Use this for equivalence or implication checks.
NOT, AND, OR, XOR, NAND, NOR, ->, <->, !, &, |, ^
Constants TRUE, FALSE, T, F, 1, and 0 are accepted.

Example Data Table

Purpose Primary formula Comparison formula Expected check
Modus ponens ((p -> q) AND p) -> q Tautology
De Morgan law NOT (p AND q) NOT p OR NOT q Equivalent
Exclusive choice p XOR q (p OR q) AND NOT (p AND q) Equivalent
Invalid implication p OR q p AND q Not valid

Formula Used

The calculator evaluates each assignment with standard propositional rules. Negation is ¬P. Conjunction is P ∧ Q. Disjunction is P ∨ Q. Exclusive OR is true when only one side is true.

Implication uses P → Q = ¬P ∨ Q. Biconditional uses P ↔ Q, which is true when both sides match. NAND means ¬(P ∧ Q). NOR means ¬(P ∨ Q).

DNF joins true rows with OR. Each true row becomes an AND term. CNF joins false-row clauses with AND. Each false row creates one OR clause that rejects that row.

How to Use This Calculator

  1. Enter a primary proposition in the first box.
  2. Enter a second proposition when checking equivalence or implication.
  3. Choose alphabetical order or first appearance order for variables.
  4. Select normal forms when the expression has a practical variable count.
  5. Press the calculate button and read the result above the form.
  6. Use CSV or PDF export to save the truth table.

Understanding the Calculator

Discrete mathematics uses logic to test whether statements are sound. This calculator turns symbolic propositions into a complete truth table. It also checks tautologies, contradictions, contingencies, equivalence, and implication. You can use it for homework, tutoring, proofs, software rules, and digital circuit ideas.

Why Logic Tables Matter

A truth table lists every possible truth assignment for the variables in a proposition. Each row shows one case. The final column shows whether the statement is true or false under that case. This makes hidden patterns visible. It also prevents guessing. When every row is true, the formula is a tautology. When every row is false, it is a contradiction. Mixed results mean the formula is a contingency.

Advanced Logic Checks

Advanced logic work often compares two formulas. Two formulas are equivalent when they match in every row. An implication is valid when no row makes the premise true and the conclusion false. This calculator checks both conditions. It also creates disjunctive and conjunctive normal forms when the variable count is practical. These forms help with proof writing, switching algebra, and simplification.

Input Syntax

Enter variables with letters such as p, q, and r. Use NOT, AND, OR, XOR, NAND, NOR, implication, and biconditional operators. Parentheses help control order. The calculator uses standard precedence, so negation is handled first. Conjunction follows. Then exclusive logic and disjunction are evaluated. Implication and biconditional checks are handled last.

Export and Review

The result area appears before the form after calculation. This keeps the answer easy to find. You can export the current truth table as a CSV file for spreadsheets. You can also save a PDF for sharing, printing, or class notes. The example table gives ready formulas to test. It is useful when you want to learn the accepted syntax quickly.

Study Benefit

This tool is meant for careful reasoning, not only quick answers. Review the classification summary first. Then scan the counterexample rows if a rule fails. Finally, compare the generated normal forms with your class method. That routine builds strong logic habits and reduces mistakes in discrete mathematics.

Because every row is produced directly from the operators, the work stays transparent. You can copy the table into reports, compare manual answers, and find the exact assignment that breaks a proposed theorem before final submission or review.

FAQs

What does this logic calculator do?

It builds truth tables, classifies formulas, checks satisfiability, tests equivalence, and validates implication between two logic expressions.

Which operators can I use?

You can use NOT, AND, OR, XOR, NAND, NOR, implication, and biconditional symbols. Short forms like !, &, |, ^, ->, and <-> also work.

What is a tautology?

A tautology is a proposition that is true under every possible variable assignment. The truth table has only true results.

What is a contradiction?

A contradiction is false under every assignment. It has no satisfying row, so the calculator marks it as unsatisfiable.

How is implication tested?

The calculator checks whether A -> B is true in every row. It fails only when A is true and B is false.

How is equivalence tested?

Two formulas are equivalent when their truth values match in every row. Any mismatch creates a counterexample row.

Why are normal forms sometimes skipped?

CNF and DNF can become very long with many variables. The calculator limits them to practical cases for readability.

Can I save my results?

Yes. Use the CSV button for spreadsheet work. Use the PDF button for sharing, printing, or adding results to notes.

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Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.