Boolean algebra and minimisation

Boolean algebra is the arithmetic of two values, and every tool in this section is a different view of the same object: an expression, a table, a map, a list of rows. Enter a function in any one of them and the rest follow.

The seven tools

The one thing worth knowing before you start

A Karnaugh map grouping is three algebra steps. Two cells that differ in one variable give t·x + t·x′; factor with the Distributive law to get t·(x + x′); the Complement law makes the bracket 1; the Identity law drops it, leaving t. That chain — usually named the Adjacency or Combining law — is why a group of two removes one literal, a group of four removes two, and a group of eight removes three.

How we know the answers are right

Minimisation runs Quine–McCluskey to a proven minimum before any explanation is written, so the working narrates a result that is already known to be optimal rather than stopping wherever the rewrite rules run out. Every emitted step is checked against the original function’s truth table in test builds. The full test suite, including the exhaustive check over all 65,536 functions of four variables, is published.

How the answers are computed, in full →

Related

  • Gates & Circuits

    What each gate does, in both symbol standards, and how to build circuits out of them.

  • Numbers & Codes

    Convert between bases and representations, and check the codes that detect and fix errors.

  • Logic gate symbols

    Every gate in both symbol standards, side by side, on a printable one-page chart.