1 Preliminaries

These notes

These notes are divided into six parts.

Part I, contains preliminary information which is good to know before starting to read the rest of the material.

Part II is about writing and using conceptual graphs in Prolog+CG. We will only say as much about Prolog as is necessary for understanding how to use Prolog+CG to represent conceptual graphs. Part II includes a number of examples that will highlight how conceptual graphs can be useful in a computational framework.

Part III, is a general introduction to Prolog. We will describe and explain Prolog in its basic, general form, only saying a little that is specific to Prolog+CG. Thus Part III should enable you to understand how Prolog works, and also how to write general Prolog programs.

Part IV, is about Peirce's rules of inference. Peirce developed five rules of inference using contexts which can be used as a general-purpose logic. Part IV introduces a variant of these rules that has been adapted for conceptual graphs. Using these five rules of inference, it is possible to reason using conceptual graphs.

Part V contains some exercises.

Part VI contains some reference materials.


Scattered throughout the text of these notes will be links to the Glossary. Use these links whenever you want to. Some of the terms used are only defined in the glossary, while they are used with little or no explanation in the running text. Therefore, if there are any terms you don't know, using the glossary may prove to be a fruitful use of time.

You can see when a link points to the glossary by looking at the place in your browser where the URL of the link under the mouse is shown. If this URL contains the word "Glossary", it is a link to the glossary.


On many of the following pages, there will be a short summary at the bottom of the page highlighting the main points of the page. Use these summaries to make sure you understand the main points.

Document hierarchy

The following pages are divided into parts, chapters, and pages. The table of contents lists all of the pages indented in such a way as to indicate the document hierarchy. Each chapter will start with a list of the pages in the chapter.

At the bottom of each page, there will be three links: Prev, Up, and Next. These take you to the previous, once upwards, and next pages in the document hierarchy. You will always be able to get to the table of contents by clicking "Up" a number of times.

"Lite" track

The course has a "lite" track which avoids advanced material. The links named "PrevLite" and "NextLite" at the bottom of each page will take you through this track.

The advanced sections can be reached either through the "Prev/Next" links described in the previous section, or through the navigation menu on the left. They are clearly marked with the symbol "(Ad)" in the title.


At the end of most chapters, there will be a quiz. This will be a multiple-choice quiz where you have to pick an answer from a number of possibilities. Only one possibility will be correct.

When you are done picking your answers, click the button at the bottom of the page. You will see a tally indicating how many questions you got right. Then those questions that you got wrong are printed again, with the correct answer and an explanation.

If you want to see all questions with correct answers and explanations, there is a possibility of displaying them by clicking another button. Otherwise, you can click "Next" to go on to the next chapter.


If there is anything that is unclear in these pages, we would like to hear about it. You can write to Ulrik Petersen at "ulrikp at hum.aau.dk" (convert this to a valid e-mail address before sending the e-mail). It is most helpful if you indicate which page you are referring to by including its node number. This is the four- or five-digit number you see in the Address field of your browser.


These notes are about how to use conceptual graphs, both in a computational framework using Prolog+CG, and in a formal framework using Peirce's five rules of inference.

Part I gives useful background information. Part II introduces how to write and make use of conceptual graphs in Prolog+CG. Part III is a general introduction to Prolog. Part IV introduces Peirce's five rules of inference in a CG framework. Part V contains some exercises. Part VI contains reference materials.


The next page gives hints on how to download and install the Prolog+CG environment if you want to do this on your own machine. The whole package has already been installed on the machines in the laboratories at Kroghstræde 3.

PrevLite: Part I: Foundations
NextLite: 1.1 Downloading and installing the Prolog+CG environment

Prev: Part I: Foundations
Up: Part I: Foundations
Next: 1.1 Downloading and installing the Prolog+CG environment