derivations

Fast Start on Web Page presentations (for Instructors) martin Thu, 10/16/2014 - 17:20

10/15/14  under construction

[Deriver works in the form either of javascript widgets, which appear directly in a web page viewed through a web browser, or as a downloadable java application, which runs like any other application (usually off the desktop on your computer).]

With the widgets in web pages, it should be fairly clear what the possibilities are. The downloaded application offers more, but at the cost of being more complex.)

Further help with Reductio admin Tue, 01/14/2014 - 14:25
Logical System

Example of a difficult derivation

6/1/09


Try your own derivations admin Sat, 01/11/2014 - 01:50
Logical System

Roll your own derivations

2013

You may have derivations of your own that you wish to try. Just type, paste, or drag and drop, them into the panel, select your derivation, and click 'Start from selection'. [Often copy-and-paste won't work directly from a Web Page; however, usually drag-and-drop will work!]

You will need to use the correct logical symbols. Here they are

F ∴ F & G ∼ & ∨ ⊃ ≡ ∀ ∃ ∴ (or use the palette to produce them)

Help with Tutorial 25h admin Sat, 01/11/2014 - 01:50
Logical System

4/24/06

Tutorial 25 Exercises h

Help with Tutorial 25g admin Sat, 01/11/2014 - 01:50
Logical System

4/24/06

Tutorial 25 Exercises g

Help with Tutorial 25e admin Sat, 01/11/2014 - 01:50
Logical System

4/24/06

Tutorial 25 Exercises e

Help with Tutorial 25d admin Sat, 01/11/2014 - 01:50
Logical System

4/24/06

Tutorial 25 Exercises d

Help with Tutorial 25abc admin Sat, 01/11/2014 - 01:50
Logical System

4/24/06

Tutorial 24: The restrictions on the quantificational rules admin Sat, 01/11/2014 - 01:50
Logical System
12/25/13

Skill to be acquired:

To understand how the various restrictions on the quantificational rules work to exclude certain kinds of invalid inferences

Reading

Bergmann[2004] The Logic Book Section 10.1

The Tutorial

The Rule of Universal Elimination UE

If a derivation contains a line of the form

n (∀<variable>)<scope> <any justification>

then a line of the form

Tutorial 21: Existential Elimination admin Sat, 01/11/2014 - 01:50
Logical System

2013

Reading

Bergmann[2004] The Logic Book Section 10.1.

The Tutorial


Existential Elimination (often called 'Existential Instantiation') permits you to remove an existential quantifier from a formula which has an existential quantifier as its main connective. It is one of those rules which involves the adoption and dropping of an extra assumption (like ∼I,⊃I,∨E, and ≡I).


The circumstance that Existential Instantiation gets invoked looks like this.