The Deriver Application can run in a web page, without needing any installation. This means that Deriver can run on any computer that can run a web browser (i.e. pretty much any computer). The Application has several useful features. It can save, and re-open, partially or entirely completed work. New exercises, or examinations, can be written by an instructor and opened by students. There is printing. It can run a variety of logical systems, from different versions of propositional and predicate calculus, to trees, modal logic, set theory, lambda calculus etc.
Please click on one of
- Deriver as a Web Application [Default] This will open Deriver using stored preferences. If there are no stored preferences, it will open the Default system.
- Deriver as a Web Application [Bergmann] This will open Deriver using the Bergmann system. This can be changed to other systems while Deriver is running.
- Deriver as a Web Application [Gentzen] This will open Deriver using the Gentzen system. This can be changed to other systems while Deriver is running.
- Deriver as a Web Application [Howson] This will open Deriver using the Howson system. This can be changed to other systems while Deriver is running.
Deriver will ask you for a User name and password, which are 'logic' and 'logic' . When it launches it will take about 10 seconds to display a splash-screen, then another 15 seconds before Deriver itself appears.
It will appear as a 'window' (or 'browser') within a web page. Sometimes it is more convenient for Deriver to fill that web page (to make it is large as it can be, and to make re-sizing easier). Other times it is more convenient not to do this (when, for example, you are going to have two or more instances of Deriver open and be editing backwards are forwards between them). You can fill or not fill the web page by clicking the relevant icons on the title bar of Deriver (it is just like going full screen or not full screen on an ordinary desktop application). If you expand Deriver, it will give you more space to work with, but it will not change any font sizes. If you would like the fonts to be larger or smaller just Zoom in or out off your web browser's View menu.
To go further, please go to Fast Start on the Application (for Instructors)
To try some exercises as examples, you have choices.
- you can download the zipped folders 10 Propositional Exercises (Gentzen syntax) or 15 Predicate Exercises (Gentzen syntax) Expand the compressed folders. Then open individual logic files in Deriver using 'Open Logic File' off the File menu.
- not everyone is keen on downloading and opening zipped files. There are alternatives. Deriver's logic files themselves are just text (they are a mix of HTML and XML). If you click on any of these links individually, your web browser (Chrome, Safari, Brave, Firefox, Edge, etc) will open the logic files as text and you can inspect them. If you then want to open any of them in Deriver, there are two ways. Perhaps the easiest is to copy the relevant link, then use the link in Deriver to 'Open Web Page' off the File menu. A second way is to use your web browser (Chrome, Safari, Brave, Firefox, Edge, etc) to save the web page to your computer (as, say PropEx3.lgc) then use 'Open Logic File' off the File menu in Deriver to open, say, PropEx3.lgc . Here are a couple of example files using the Gentzen syntax.
The above illustrative examples are using the 'Gentzen' system of propositional and predicate logic (its syntax and its rules). It is possible that the version of Deriver that you are running is not using that system. For example, you might be using a communal computer in a University lab and the person before you was using a different system. You can check what Deriver is running from the Title Bar, or from the Preferences, and, if needed, set the preferences exactly as you would like. Configuring the Deriver Application Using the Preferences In this case, you would probably want the parser set to 'gentzen' and the paletteText set to 'default'.
Deriver here uses Webswing technology. https://webswing.org Thank you to them for that.