You are now purchasing one copy of Language, Proof and Logic, 2nd edition package for $55.
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Please select a package to buy
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Please check that you are purchasing the correct package.
Our packages are not interchangeable. In particular, registration keys for
one package will not allow you to use the Grade Grinder to assess exercises from the other
The purchased products will be registered to the given name and email address.
Registration is non-transferable.
You are responsible for ensuring that your computing platform meets the requirement for running the software.
We support most current versions of the Windows and Macintosh operating systems. The Language,
Proof and Logic and Tarski's World packages are also supported on Fedora and Ubuntu Linux.
We have no plans to support Logical Reasoning with Diagrams and Sentences on any Linux platform.
See the FAQ for more details.