<span itemscope itemtype="http://schema.org/InformAction"><span style="display:none" itemprop="about" itemscope itemtype="http://schema.org/PostalAddress"><meta itemprop="description" content="Neuer Ort: Seminarraum 00.09.038"/></span><span itemprop="object" itemscope itemtype="http://schema.org/Event"><div style=""><table cellspacing="0" cellpadding="8" border="0" summary="" style="width:100%;font-family:Arial,Sans-serif;border:1px Solid #ccc;border-width:1px 2px 2px 1px;background-color:#fff;"><tr><td><meta itemprop="eventStatus" content="http://schema.org/EventRescheduled"/><h4 style="padding:6px 0;margin:0 0 4px 0;font-family:Arial,Sans-serif;font-size:13px;line-height:1.4;border:1px Solid #fff;background:#fff;color:#090;font-weight:normal"><strong>Dieser Termin wurde geändert.</strong></h4><div style="padding:2px"><span itemprop="publisher" itemscope itemtype="http://schema.org/Organization"><meta itemprop="name" content="Google Calendar"/></span><meta itemprop="eventId/googleCalendar" content="0ffld3k15f850jifqocif8tpqs"/><h3 style="padding:0 0 6px 0;margin:0;font-family:Arial,Sans-serif;font-size:16px;font-weight:bold;color:#222"><span itemprop="name">Formally Verified Certification of the Simplex Algorithm </span></h3><table style="display:inline-table" cellpadding="0" cellspacing="0" border="0" summary="Termindetails"><tr><td style="padding:0 1em 10px 0;font-family:Arial,Sans-serif;font-size:13px;color:#888;white-space:nowrap;width:90px" valign="top"><div><i style="font-style:normal">Wann</i></div></td><td style="padding-bottom:10px;font-family:Arial,Sans-serif;font-size:13px;color:#222" valign="top"><div style="text-indent:-1px"><time itemprop="startDate" datetime="20220622T123000Z"></time><time itemprop="endDate" datetime="20220622T125000Z"></time>Mi 22. Jun. 2022 14:30 – 14:50 <span style="color:#888">Mitteleuropäische Zeit - Berlin</span></div></td></tr><tr><td style="padding:0 1em 10px 0;font-family:Arial,Sans-serif;font-size:13px;color:#888;white-space:nowrap;width:90px" valign="top"><div><i style="font-style:normal">Wo</i></div></td><td style="padding-bottom:10px;font-family:Arial,Sans-serif;font-size:13px;color:#222" valign="top"><div style="text-indent:-1px"><strong style="color:#080">Geändert: </strong><span itemprop="location" itemscope itemtype="http://schema.org/Place"><span itemprop="name" class="notranslate">Seminarraum 00.09.038</span><span dir="ltr"> (<a href="https://www.google.com/maps/search/Seminarraum+00.09.038?hl=de" style="color:#20c;white-space:nowrap" target="_blank" itemprop="map">Karte</a>)</span></span></div></td></tr><tr><td style="padding:0 1em 10px 0;font-family:Arial,Sans-serif;font-size:13px;color:#888;white-space:nowrap;width:90px" valign="top"><div><i 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href="https://calendar.google.com/calendar/event?action=VIEW&eid=MGZmbGQzazE1Zjg1MGppZnFvY2lmOHRwcXMgY2x1YjJAaW4udHVtLmRl&tok=NTIjc2U2ZWJlM3RvZmY0Y2g1bm11bmlibTVtOThAZ3JvdXAuY2FsZW5kYXIuZ29vZ2xlLmNvbWM1YzkzODZhODZlZjczMTIzZTczYzc4ZWU4NzNlYTVhYzVjNGM3NmM&ctz=Europe%2FBerlin&hl=de&es=0" style="color:#20c;white-space:nowrap" itemprop="url">Mehr Details »</a><br></div><div style="padding-bottom:15px;font-family:Arial,Sans-serif;font-size:13px;color:#222;white-space:pre-wrap!important;white-space:-moz-pre-wrap!important;white-space:-pre-wrap!important;white-space:-o-pre-wrap!important;white-space:pre;word-wrap:break-word"><span>Speaker: Adem Rimpapa<br> <br>Abstract: Simplex solvers can be used to efficiently determine whether a linear program is feasible or infeasible. Directly verifying practical, optimised simplex solvers is often difficult due to the complexity of their code. Certification of simplex results is an alternative<br>approach to direct verification which involves tracing the algebraic operations of the simplex solver to produce a certificate, a proof of feasibility or infeasibility of a particular linear program. Certificates are checked using a piece of code called the certificate checker, which needs to be formally verified. This thesis provides an implementation of a certificate checker, a certificate parser, and modifications to a simplex solver for the purpose of certificate generation. The certificate checker is implemented in the interactive theorem prover Isabelle/HOL, with the end goal being verification of<br>soundness and completeness of the certificate checker. The code was evaluated on two example datasets. The first dataset only produced certificates for feasible linear programs and were all checked as valid by the certificate checker. The second dataset produced certificates for infeasible linear programs, most of which were declared to be invalid by the certificate checker. The results of the second dataset still need to be examined, since they could potentially lead to the discovery of a mistake in one of the components of the code.</span><meta itemprop="description" content="Speaker: Adem Rimpapa
Abstract: Simplex solvers can be used to efficiently determine whether a linear program is feasible or infeasible. Directly verifying practical, optimised simplex solvers is often difficult due to the complexity of their code. Certification of simplex results is an alternative
approach to direct verification which involves tracing the algebraic operations of the simplex solver to produce a certificate, a proof of feasibility or infeasibility of a particular linear program. Certificates are checked using a piece of code called the certificate checker, which needs to be formally verified. This thesis provides an implementation of a certificate checker, a certificate parser, and modifications to a simplex solver for the purpose of certificate generation. The certificate checker is implemented in the interactive theorem prover Isabelle/HOL, with the end goal being verification of
soundness and completeness of the certificate checker. The code was evaluated on two example datasets. The first dataset only produced certificates for feasible linear programs and were all checked as valid by the certificate checker. The second dataset produced certificates for infeasible linear programs, most of which were declared to be invalid by the certificate checker. The results of the second dataset still need to be examined, since they could potentially lead to the discovery of a mistake in one of the components of the code."/></div></div><p style="color:#222;font-size:13px;margin:0"><span style="color:#888">Teilnehmen (club2@in.tum.de)? </span><wbr><strong><span itemprop="potentialaction" itemscope itemtype="http://schema.org/RsvpAction"><meta itemprop="attendance" content="http://schema.org/RsvpAttendance/Yes"/><span itemprop="handler" itemscope itemtype="http://schema.org/HttpActionHandler"><link itemprop="method" href="http://schema.org/HttpRequestMethod/GET"/><a href="https://calendar.google.com/calendar/event?action=RESPOND&eid=MGZmbGQzazE1Zjg1MGppZnFvY2lmOHRwcXMgY2x1YjJAaW4udHVtLmRl&rst=1&tok=NTIjc2U2ZWJlM3RvZmY0Y2g1bm11bmlibTVtOThAZ3JvdXAuY2FsZW5kYXIuZ29vZ2xlLmNvbWM1YzkzODZhODZlZjczMTIzZTczYzc4ZWU4NzNlYTVhYzVjNGM3NmM&ctz=Europe%2FBerlin&hl=de&es=0" style="color:#20c;white-space:nowrap" itemprop="url">Ja</a></span></span><span style="margin:0 0.4em;font-weight:normal"> - </span><span itemprop="potentialaction" itemscope itemtype="http://schema.org/RsvpAction"><meta itemprop="attendance" content="http://schema.org/RsvpAttendance/Maybe"/><span itemprop="handler" itemscope itemtype="http://schema.org/HttpActionHandler"><link itemprop="method" href="http://schema.org/HttpRequestMethod/GET"/><a href="https://calendar.google.com/calendar/event?action=RESPOND&eid=MGZmbGQzazE1Zjg1MGppZnFvY2lmOHRwcXMgY2x1YjJAaW4udHVtLmRl&rst=3&tok=NTIjc2U2ZWJlM3RvZmY0Y2g1bm11bmlibTVtOThAZ3JvdXAuY2FsZW5kYXIuZ29vZ2xlLmNvbWM1YzkzODZhODZlZjczMTIzZTczYzc4ZWU4NzNlYTVhYzVjNGM3NmM&ctz=Europe%2FBerlin&hl=de&es=0" style="color:#20c;white-space:nowrap" itemprop="url">Vielleicht</a></span></span><span style="margin:0 0.4em;font-weight:normal"> - </span><span itemprop="potentialaction" itemscope itemtype="http://schema.org/RsvpAction"><meta itemprop="attendance" content="http://schema.org/RsvpAttendance/No"/><span itemprop="handler" itemscope itemtype="http://schema.org/HttpActionHandler"><link itemprop="method" href="http://schema.org/HttpRequestMethod/GET"/><a href="https://calendar.google.com/calendar/event?action=RESPOND&eid=MGZmbGQzazE1Zjg1MGppZnFvY2lmOHRwcXMgY2x1YjJAaW4udHVtLmRl&rst=2&tok=NTIjc2U2ZWJlM3RvZmY0Y2g1bm11bmlibTVtOThAZ3JvdXAuY2FsZW5kYXIuZ29vZ2xlLmNvbWM1YzkzODZhODZlZjczMTIzZTczYzc4ZWU4NzNlYTVhYzVjNGM3NmM&ctz=Europe%2FBerlin&hl=de&es=0" style="color:#20c;white-space:nowrap" itemprop="url">Nein</a></span></span></strong> <wbr><a href="https://calendar.google.com/calendar/event?action=VIEW&eid=MGZmbGQzazE1Zjg1MGppZnFvY2lmOHRwcXMgY2x1YjJAaW4udHVtLmRl&tok=NTIjc2U2ZWJlM3RvZmY0Y2g1bm11bmlibTVtOThAZ3JvdXAuY2FsZW5kYXIuZ29vZ2xlLmNvbWM1YzkzODZhODZlZjczMTIzZTczYzc4ZWU4NzNlYTVhYzVjNGM3NmM&ctz=Europe%2FBerlin&hl=de&es=0" style="color:#20c;white-space:nowrap" itemprop="url">Weitere Optionen »</a></p></td></tr><tr><td style="background-color:#f6f6f6;color:#888;border-top:1px Solid #ccc;font-family:Arial,Sans-serif;font-size:11px"><p>Einladung von <a href="https://calendar.google.com/calendar/" target="_blank" style="">Google Kalender</a></p><p>Sie erhalten diese E-Mail unter club2@in.tum.de, da Sie ein Gast bei diesem Termin sind.</p><p>Lehnen Sie diesen Termin ab, um keine weiteren Informationen zu diesem Termin zu erhalten. Sie können auch unter https://calendar.google.com/calendar/ ein Google-Konto erstellen und Ihre Benachrichtigungseinstellungen für Ihren gesamten Kalender steuern.</p><p>Wenn Sie diese Einladung weiterleiten, kann jeder Empfänger eine Antwort an den Organisator senden und zur Gästeliste hinzugefügt werden. Außerdem könnte er weitere Nutzer einladen und Ihre Antwort ändern. <a href="https://support.google.com/calendar/answer/37135#forwarding">Weitere Informationen</a>.</p></td></tr></table></div></span></span>