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<B>Links</B><BR>+ −
<A HREF="http://www4.in.tum.de/~urbanc/index.html">Home</A><BR>+ −
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<B>Java Versions</B><BR>+ −
<A HREF="http://www4.in.tum.de/~urbanc/Cut/CL.html">CL</A><BR>+ −
<A HREF="http://www4.in.tum.de/~urbanc/Cut/LJT.html">LJT</A><BR>+ −
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<B>Plugin Versions</B><BR>+ −
<A HREF="http://www4.in.tum.de/~urbanc/Cut/CL-plugin.html">CL</A><BR>+ −
<A HREF="http://www4.in.tum.de/~urbanc/Cut/LJT-plugin.html">LJT</A><BR>+ −
<A HREF="http://www4.in.tum.de/~urbanc/Cut/ND-plugin.html">ND</A><BR>+ −
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<H2>Cut-Elimination in Herbelin's calculus for intuitionistic logic</H2>+ −
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Recommended reading for this applet is a paper by Dyckhoff and Urban, + −
[<A HREF="http://www-theory.dcs.st-and.ac.uk/~rd/publications/MJES/DyckhoffUrbanWestApp01.rev.ps">ps</A>,+ −
<A HREF="http://www-theory.dcs.st-and.ac.uk/~rd/publications/MJES/DyckhoffUrbanWestApp01.rev.pdf">pdf</A>].+ −
Mayor difference between the standard sequent calculus and Herbelin's sequent calculus + −
is that in the cut-free fragment "there are no semantically + −
trivial permutations of the inference rules, where by 'semantically trivial' we mean + −
'interpreted in NJ as true equations between to (normal) deductions'" + −
(from [<A HREF="http://www-theory.dcs.st-and.ac.uk/~rd/publications/SLPaper.corr.ps">ps</A>]). + −
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<B>How to use it?</B> + −
If your browser is working correctly, then you will see a window + −
with two examples (more added if you suggest some). When pressing on + −
one of the buttons, a new window will pop up. What follows + −
is a brief explanation of all the features available in this window. + −
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<B>Buttons and Keys</B>+ −
<UL>+ −
<LI> The buttons + −
<IMG SRC="http://www4.in.tum.de/~urbanc/Cut/x.jpg"> + −
`fire' cuts (not all cuts necessarily have such buttons). + −
<LI> If you use the <B>left mouse button</B> for pressing on those buttons,+ −
then the new proof will appear inside the window. Whereas if you use + −
the <B>right mouse button</B>, a new window will pop up and + −
the new proof will be displayed in this window. Use the right mouse + −
button if you want to compare a proof and its reduct.+ −
<LI> The keys <B>Page-up</B> and <B>Page-down</B> zoom in or out of a proof+ −
respectively. + −
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<B>Menu Functions</B>+ −
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<UL>+ −
<LI> <B>Zoom in</B> and <B>Zoom out</B> work like Page-up and Page-down, + −
respectively.+ −
<LI> <B>Unicode</B> If this radiobutton is switched on, logic symbols + −
are displayed in unicode, otherwise in ascii. (This is for the + −
poor guys who have a browser and/or operating system which cannot handle + −
unicode.)+ −
<LI> <B>Labels</B> As mentioned earlier the sequents are composed of + −
two sets of labelled + −
formulae, not multisets of formulae as in the standard formulation + −
of sequent calculus. Enabling this radiobutton causes that labels are + −
drawn. Use this when you are unsure where implicit contractions are. + −
<LI> <B>Compact printing</B> In the paper referred above weakening+ −
is done only in axioms. If this radiobutton is switched on (default),+ −
then, in order to save space, formulae are weakened as soon as possible.+ −
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<applet archive=MyApplet.zip code="MyApplet.class" width=1 height=1>+ −
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Applet should appear in a new window, but you don't have Java enabled in your browser.+ −
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