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4 <TITLE>Homepage of Christian Urban</TITLE> |
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28 |
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29 <B>Links</B><BR> |
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30 <A HREF="http://www4.in.tum.de/~urbanc/index.html">Home</A><BR> |
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31 <A HREF="http://www4.in.tum.de/~urbanc/publications.html">Publications</A><BR> |
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32 <A HREF="http://www4.in.tum.de/~urbanc/teaching.html">Teaching</A><BR> |
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33 <A HREF="http://www4.in.tum.de/~urbanc/travelling.html">Recent Talks</A><BR> |
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34 <A HREF="http://isabelle.in.tum.de/nominal/">My Research Group</A> |
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35 <BR> |
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36 <BR> |
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37 |
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38 <B>Handy Information</B><BR> |
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39 <A HREF="http://www4.in.tum.de/~urbanc/logic.html">People in Logic</A><BR> |
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40 <A HREF="http://www4.in.tum.de/~urbanc/programming.html">Programming Languages</A><BR> |
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41 <A HREF="http://www4.in.tum.de/~urbanc/misc.html">Miscellaneous</A> |
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42 <BR><BR> |
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43 |
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44 <A HREF="http://isabelle.in.tum.de/nominal/"> |
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52 <A NAME="Home"></A> |
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53 <TABLE> |
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55 <TD WIDTH="75%"> |
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56 <H1>Christian Urban </H1> |
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57 |
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58 <B>E-mail</B> |
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59 urbanc <I>at</I> in tum de<BR> |
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60 <BR> |
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61 |
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62 <B>Address</B> |
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63 <A HREF="http://www.in.tum.de/en.html">Institute for Computer Science</A> |
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64 at the TU Munich (IV), Boltzmannstrasse 3, D-85748 Garching, Germany. |
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65 <BR><BR> |
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66 |
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67 <B>Fax</B> +49 89 289 17307 |
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68 </TD> |
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69 <TD align="right" valign="top"> |
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70 <A HREF="http://www4.in.tum.de/~urbanc/picture-small.jpg"><IMG ALT="" SRC="picture-small.jpg" align="top"></A> |
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73 </TABLE> |
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74 <p> |
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75 <IMG SRC="new.gif" ALT="" style="" align="left"><A HREF="http://isabelle.in.tum.de/nominal/activities/idp" target="_top">Isabelle Documentation Project</A> (contains now a draft of a 200-page tutorial on Isabelle programming)<BR> |
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76 </TD> |
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77 </TR> |
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78 |
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79 <TR> |
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80 <TD BGCOLOR="#FFFFFF" WIDTH="75%"> |
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81 <B>Current Position</B> |
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82 I have been awarded an |
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83 <A HREF="http://en.wikipedia.org/wiki/Emmy_Noether">Emmy-Noether</A> |
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84 <A HREF="http://www.dfg.de/en/research_funding/programmes/individual/emmy_noether/in_brief/index.html">fellowship</A> |
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85 to head an independent <A HREF="http://isabelle.in.tum.de/nominal/">research group</A> in |
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86 the Computer Science Department at the |
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87 <A HREF="http://www.in.tum.de/en.html">TU Munich</A>. This group co-operates |
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88 with the <A HREF="http://www4.in.tum.de/proj/theoremprov/group.html">Theorem Proving Group</A> |
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89 chaired by <A HREF="http://www4.informatik.tu-muenchen.de/~nipkow/">Prof. Tobias Nipkow</A> and |
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90 is accommodated by the institute of |
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91 <A HREF="http://www4.informatik.tu-muenchen.de/~broy/">Prof. Manfred Broy</A>. |
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92 <P> |
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93 |
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94 <B>Past Positions</B> |
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95 Between September 2008 and February 2009, I was an invited research fellow in |
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96 the <A HREF="http://www.cs.princeton.edu/">Department of Computer Science</A> in Princeton. |
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97 In 2004/05 I was an Alexander-von-Humboldt fellow in Munich and |
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98 from 2000 until 2004 I was awarded a Research Fellowship in Cambridge. Before that |
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99 I did my PhD in Cambridge. |
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100 <P> |
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101 |
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102 <B>Research Interests</B> theorem provers, programming languages, compilers, |
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103 algorithms, proof theory, type systems, concurrency, lambda calculus, unification, |
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104 regular expressions, computability, complexity, functional and logic programming. |
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105 <P> |
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106 |
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107 <B>Conferences</B> |
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108 <A HREF="http://www.iiia.csic.es/~levy/unif06/">UNIF'06</A> (member of PC), |
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109 <A HREF="http://www.cs.mcgill.ca/~bpientka/lfmtp07">LFMTP'07</A> (member of PC), |
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110 <A HREF="http://isabelle.in.tum.de/nominal/activities/lfmtp08/">LFMTP'08</A> (PC co-chair), |
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111 <A HREF="http://www.cis.upenn.edu/~sweirich/wmm/">WMM'08</A> (member of PC), |
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112 <A HREF="http://www.mat.ufmg.br/lsfa2008/">LSFA'08</A> (invited speaker), |
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113 <A HREF="http://www.dcs.kcl.ac.uk/staff/maribel/TAASN.html">TAASN'09</A> (member of PC), |
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114 <A HREF="http://lsfa09.cic.unb.br/">LSFA'09</A> (member of PC), |
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115 <A HREF="http://isabelle.in.tum.de/nominal/activities/tphols09/idw.html">IDW'09</A> (organiser), |
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116 <A HREF="http://www.seas.upenn.edu/~sweirich/wmm/wmm09.html">WMM'09</A> (PC chair), |
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117 <A HREF="http://tphols.in.tum.de/">TPHOLs'09</A> (PC co-chair), |
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118 <A HREF="http://dream.inf.ed.ac.uk/events/automatheo-2010/">Automatheo'10</A> (member of PC), |
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119 <A HREF="http://www.floc-conference.org/">ITP'10</A> (member of PC), |
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120 <A HREF="http://www.dcs.kcl.ac.uk/staff/maribel/UNIF.html">UNIF'10</A> (invited speaker), |
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121 <A HREF="http://www.cis.upenn.edu/~bcpierce/wmm/">WMM'10</A> (invited speaker), |
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122 <A HREF="http://isabelle.in.tum.de/nominal/activities/idw10/idw.html">IDW'10</A> (co-organiser), |
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123 <A HREF="http://formes.asia/cpp">CPP'11</A> (member of PC), |
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124 <A HREF="http://www.rdp2011.uns.ac.rs/rta/">RTA'11</A> (member of PC), |
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125 <A HREF="http://lfmtp11.cs.umn.edu">LFMTP'11</A> (member of PC) |
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126 <BR> |
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127 |
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128 </TD> |
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130 |
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131 <TR> |
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132 <TD BGCOLOR="#FFFFFF" WIDTH="75%"> |
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133 <B>Nominal Isabelle</B> |
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134 I currently work on Nominal |
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135 <A HREF="http://isabelle.in.tum.de">Isabelle</A>. This is joint work with |
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136 <A HREF="http://wwwbroy.in.tum.de/~berghofe/">Dr Stefan Berghofer</A>, |
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137 <A HREF="http://www4.in.tum.de/~wenzelm/">Dr Markus Wenzel</A>, |
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138 <A HREF="http://www4.in.tum.de/~kaliszyk/">Dr Cezary Kaliszyk</A> and |
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139 the Isabelle-team in Munich. |
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140 Many of the theoretical ideas originate from the nominal logic project - a wonderful project headed |
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141 by <A HREF="http://www.cl.cam.ac.uk/~amp12/">Prof. Andrew Pitts</A>. |
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142 The aim of my work is to make formal reasoning involving binders as simple as |
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143 on paper and the hope is to lure |
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144 <A HREF="http://alliance.seas.upenn.edu/~plclub/cgi-bin/poplmark/index.php?title=The_POPLmark_Challenge#Vision">masses</A> to automated |
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145 theorem proving. My funding for this work was provided in 2004 and 2005 by a research |
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146 fellowship from the |
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147 <A HREF="http://en.wikipedia.org/wiki/Alexander_von_Humboldt">Alexander-von-Humboldt</A> |
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148 <A HREF="http://www.humboldt-foundation.de/web/home.html">foundation</A>. During this time I was a visitor in the group of |
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149 <A HREF="http://www.mathematik.uni-muenchen.de/~schwicht/">Prof. Helmut Schwichtenberg</A>. |
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150 Since 2006 this work is supported by an |
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151 <A HREF="http://en.wikipedia.org/wiki/Emmy_Noether">Emmy-Noether</A> |
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152 <A HREF="http://www.dfg.de/en/research_funding/programmes/individual/emmy_noether/in_brief/index.html">fellowship</A>. |
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153 There is a <A HREF="http://isabelle.in.tum.de/nominal/">webpage</A> and a |
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154 <A HREF="https://mailmanbroy.informatik.tu-muenchen.de/mailman/listinfo/nominal-isabelle">mailing list</A> |
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155 about Nominal Isabelle. It also includes a list of projects that use Nominal Isabelle. |
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156 Users of Nominal Isabelle had their papers appearing at LICS, POPL, FOSSACS, SOS, TPHOLs and CPP. |
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157 </TD> |
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158 </TR> |
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159 |
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160 <TR> |
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161 <TD BGCOLOR="#FFFFFF" WIDTH="75%"> |
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162 <B>Myhill-Nerode and Regular Expressions</B> |
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163 Out of frustration of having to teach inductions in theorem provers using worn-out examples like |
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164 fib and even/odd, we implemented a large part of regular language theory in Isabelle/HOL. |
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165 This <A HREF="http://afp.sourceforge.net/devel-entries/Myhill-Nerode.shtml">implementation</A> |
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166 gives rise to much more interesting examples, as shown |
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167 <A HREF="http://www.cs.cmu.edu/~rwh/papers/regexp/jfp.ps">here</A> and |
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168 <A HREF="http://ropas.snu.ac.kr/~kwang/paper/06-jfp-yi.pdf">here</A>. It turns out that |
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169 formalisations of automata theory are a huge |
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170 <A HREF="https://lists.cam.ac.uk/pipermail/cl-isabelle-users/2005-September/msg00012.html">pain</A> |
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171 in theorem provers, especially in those that are HOL-based. |
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172 We therefore went against the |
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173 <A HREF="http://books.google.com/books?id=8lKyxS8_CNoC&pg=PA14&source=gbs_toc_r&cad=4#v=onepage&q&f=false">mainstream</A> |
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174 and used in our formalisation regular expressions exclusively, |
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175 because they are much more convenient for formal reasoning. The results we |
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176 formalised include: the Myhill-Nerode theorem, the closure of regular languages |
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177 under complementation, finiteness of derivatives of regular expressions and a surprising |
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178 result about Subseq, which according to |
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179 this |
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180 <A HREF="http://blog.computationalcomplexity.org/2006/01/theorem-that-should-be-better-known.html">blog</A> |
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181 should be better known. This is joint work with Prof. Xingyuan |
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182 Zhang and his student Chunhan Wu from the |
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183 <A HREF="http://www.ust.com.cn/">PLA University of Science and Technology</A> in Nanjing. |
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184 My funding for this work came from the |
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185 <A HREF="http://www.sinogermanscience.org.cn/">Chinese-German Research Centre</A>. |
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186 </TD> |
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187 </TR> |
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188 |
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189 <TR> |
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190 <TD BGCOLOR="#FFFFFF" WIDTH="75%"> |
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191 <B>Nominal Unification and Alpha-Prolog</B> |
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192 <A HREF="http://www4.in.tum.de/~urbanc/Unification">Nominal unification</A> is one outcome of |
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193 my involvement in the nominal logic project in Cambridge. Another is the logic programming language |
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194 alpha-Prolog (joint work with <A HREF="http://homepages.inf.ed.ac.uk/jcheney/">Dr James Cheney</A>), |
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195 which uses nominal unification - click for details |
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196 <A HREF="http://homepages.inf.ed.ac.uk/jcheney/programs/aprolog/">here</A>. |
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197 The nominal unification algorithm has been |
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198 <A HREF="http://www4.in.tum.de/~urbanc/Unification">formally verified</A> in Isabelle. This |
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199 was possible since this unification algorithm is formulated in a simple first-order language |
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200 (unlike other algorithms for higher-order unification). |
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201 <A HREF="http://www.cs.indiana.edu/~dfried/">Prof. Daniel Friedman</A> and his group use nominal |
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202 unification in their alpha-Kanren system implemented in Scheme. |
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203 <A HREF="http://www.dcs.kcl.ac.uk/staff/maribel/">Prof. Maribel Fernandez</A> and her student |
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204 improved the nominal unification algorithm to be quadratic. |
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205 My funding for this work was provided through a research fellowship from |
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206 <A HREF="http://www.corpus.cam.ac.uk">Corpus Christi College</A>, Cambridge. |
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207 </TD> |
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208 </TR> |
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209 |
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210 <TR> |
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211 <TD BGCOLOR="#FFFFFF" WIDTH="75%"> |
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212 <B>Classical Logic</B> |
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213 I was Ph.D. student in the University of Cambridge |
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214 <A HREF="http://www.cl.cam.ac.uk">Computer Laboratory</A> |
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215 and for three years |
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216 called Gonville and Caius College my home. I was very lucky to have |
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217 <A HREF="http://research.microsoft.com/~gmb/">Dr Gavin Bierman</A> |
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218 as supervisor. My research in Cambridge was also very much influenced by |
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219 <A HREF="http://www.dpmms.cam.ac.uk/~martin/">Prof. Martin Hyland</A>. |
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220 Some details on my thesis "Classical Logic and Computation" are |
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221 <A HREF="http://www4.in.tum.de/~urbanc/PhD/index.html">elsewhere</A>, including |
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222 a <A HREF="http://www4.in.tum.de/~urbanc/Cut/cutapplet.html">Java Applet</A> that |
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223 'visualises' some of the results from the thesis. I completed the writing of |
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224 the thesis in <A HREF="http://iml.univ-mrs.fr/ldp/">Marseille</A> in the group of |
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225 <A HREF="http://iml.univ-mrs.fr/~girard/">Prof. Jean-Yves Girard</A>. My study in |
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226 Cambridge was funded by two <A HREF="http://www.daad.de/index.html">scholarships</a> |
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227 from the German government; my year in Marseille by a TMR-fellowship from the EU. |
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228 My PhD was also one starting point for the EPSRC Project on the Semantics of Classical |
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229 Proofs. The strong normalisation result in the PhD has recently been used by |
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230 <A HREF="http://www.loria.fr/~ckirchne/hot.html">Prof. Claude Kirchner</A> and his |
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231 students to prove consistency for their superdeduction system lemuridae. |
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232 </TD> |
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233 </TR> |
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234 |
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235 |
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236 |
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237 <TR> |
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238 <TD BGCOLOR="#FFFFFF" WIDTH="75%"> |
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239 <B>Forum</B> |
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240 I implemented Forum, a programming language based on classical linear logic, |
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241 as my M.Phil. thesis. This was joint work with |
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242 <A HREF="http://www.dcs.st-and.ac.uk/~rd/">Dr Roy Dyckhoff</A>. |
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243 Details can be found |
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244 <A HREF="http://www.dcs.st-and.ac.uk/~rd/logic/nonmac/">here</A> and |
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245 <A HREF="http://www.lix.polytechnique.fr/Labo/Dale.Miller/forum/">here</A>. During my |
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246 M.Phil study I spent one month in Philadelphia invited by |
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247 <A HREF="http://www.lix.polytechnique.fr/~dale/">Prof. Dale Miller</A>. |
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248 </TD> |
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249 </TR> |
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250 |
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251 <TR> |
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252 <TD BGCOLOR="#FFFFFF" WIDTH="75%"> |
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253 <B>G4ip</B> An implementation of G4ip using the imperative language Pizza can be found |
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254 <A HREF="http://www4.in.tum.de/~urbanc/Prover/index.html">here</A>. |
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255 <A HREF="http://pizzacompiler.sourceforge.net">Pizza</A> is a conservative |
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256 extension of Java and a precursor of Scala. The implementation illustrates the technique of success |
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257 continuations. |
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258 </TD> |
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259 </TR> |
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260 |
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261 |
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262 </TABLE> |
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