LogicTutor

LogicTutor is an offline-first study toolkit for propositional logic, built for students and teachers. Enter a formula once and get live validation with a LaTeX preview, a complete truth table, step-by-step CNF/DNF conversion and a full satisfiability report - all computed on your device, with no account and no internet required. FORMULA ANALYSIS - Type with the built-in symbol bar: not, and, or, xor, implies, iff and parentheses. - ASCII friendly: -> and && are converted automatically. - Live validation reports syntax errors as you type. - Preview your formula as typeset LaTeX, with an HD rendering option. TRUTH TABLES - Complete row-by-row tables for formulas with up to 10 variables. - Every row shows the value of each subexpression, not just the final result. - The app classifies your formula as a tautology, contradiction or contingent. - Sort satisfying rows to the top to read off models at a glance. CNF / DNF CONVERSION - Step-by-step derivations: implication elimination, De Morgan, distribution. - Results are verified logically equivalent to your original formula. - Guarded conversion warns you instead of freezing on huge normal forms. SAT REASONING - Satisfiability, classification and a satisfying model for any formula. - Beyond 10 variables an on-device DPLL solver takes over - still fully offline. EXERCISE LIBRARY - 108 questions across topics: translation, precedence, truth tables, equivalence, normal forms, satisfiability and inference rules. - Fair grading: formula answers are accepted in any logically equivalent form. - A wrong-question book collects mistakes for review and clears them once mastered. - Track completed and correct counts at the top of the library. HISTORY AND REUSE - Every analysis is saved with its formula, result and source tool. - Search, favorites, and PDF export of your history. - One-tap Reuse reopens the matching tool with the formula already filled in. ARGUMENT ANALYSIS (OPTIONAL) - Turn an English argument into its premises, its conclusion and its reasoning pattern. - The extracted formulas are re-checked by the built-in engine before anything is shown, and you can correct them by hand before analyzing. - Keeps its own history, so a past argument can be reopened and reused. AI ASSISTANT (OPTIONAL) - Chat about logic, work a problem through step by step, or ask about your own saved work. - It can also act inside the app for you: analyze a formula, decide whether two formulas are equivalent, open a tool page with a formula filled in, export an analysis as a PDF, or review and tidy your history. - Anything destructive asks for your explicit confirmation first. - Every operation runs on the same deterministic engine as the manual tools. - Keep several chats; they stay on your device. OPTIONAL AI, YOUR OWN KEY - Off by default. Nothing is sent anywhere until you enable it and add a key. - Works with OpenAI, Anthropic and Gemini out of the box, or any compatible custom endpoint. - Your key is stored in the iOS Keychain, and requests go straight from your device to the provider you pick - never through us. PDF EXPORT - Export truth tables, derivations, SAT reports, argument analyses and history as PDFs via the iOS share sheet. DESIGNED FOR IPHONE AND IPAD - Light and dark modes, adjustable formula font size, and a layout that adapts to both screens. WHO IT IS FOR - Students in discrete math, computer science, philosophy and linguistics courses. - Teachers preparing examples, exercises and handouts. - Anyone who wants a fast, reliable logic calculator in their pocket. WHY LOGICTUTOR - Deterministic on-device engine: identical, verifiable results every time - no hallucinations. - Offline-first: everything works without a network; your data never leaves your device. - Privacy by design: no account, no tracking, no analytics. - Built on Apple system frameworks only, with no third-party libraries.