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Brent Yorgey
Worked at University of Pennsylvania
Attended Williams College
Lives in Conway, AR
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Brent Yorgey

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Celebrating with ice cream cones since someone counted to 100 all by himself. He chose strawberry with gummy bears mixed in. 
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Yeah, Noah!!!!!  Way to go!  I'm very proud of you - counting to 100 all by yourself!
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I've been on a physical-object-making kick recently. It's the perfect mindful-yet-relaxing thing to do between pomodoros.
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+Debbie Yorgey , I didn't even know "pomodoro" had anything to do with tomatoes. It makes sense in retrospect.
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New office!
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Dad, no blackbaord yet, but there are promising signs that it will happen eventually!
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"Hold my jacket!  HOLD MY JACKET!!"
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You'll have to host a Haskell symposium there!!
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My third game of Go with Noah (3 yrs =)
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Have him in circles
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Me in my native habitat. (My fancy Penn regalia just arrived!)
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+Felipe Lessa, thanks =)
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Lazy Saturday with my favorite 4-year old.
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Daaaaaaaad, are you taking PICTURES again?
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Python's inconsistent handling of mutable vs immutable (strings are immutable; lists are mutable; some list methods modify the list in place; some return a new list; etc.) is making me angry.  I don't know how I'm going to teach this to freshmen without going off on a rant.
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+Jason Bandlow, thanks, that does actually help me keep things straight.  But there is no way first-semester CS students are going to be able to keep the mutable/immutable and method of/function on distinctions straight.  They are going to write things like  word.upper() and  list2 = list1.sort()  all over the place and be very confused why their word is still lowercase or why they get a runtime error when they try to use list2.
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Our paper has been accepted for the 2015 Mathematics of Program Construction Conference:

Polynomial Functors Constrained by Regular Expressions
http://dept.cs.williams.edu/~byorgey/pub/type-matrices.pdf

It's based on some blog posts from a couple of years ago and shows how to define a tree type in a language like Haskell where the leaves of the tree are constrained to match a regular expression. A basic example that many are familiar with is the type of lists where the elements alternate between two types. The picture corresponds to an example of a binary tree with regular expression b*1a* where 1 is the type with just one inhabitant so it functions as a "hole". These types have the property that it's completely impossible to build a tree that fails to satisfy the constraint.

As a side effect it also shows how you can think of Conor McBride's Jokers and Clowns paper as really being about divided differences (ie. (f(x)-f(y))/(x-y)) applied to types, even though you can't literally divide types: https://personal.cis.strath.ac.uk/conor.mcbride/Dissect.pdf

Sadly it's hard to find a programming language that can truly automate this process, especially as it involves matrices whose entries are types. Brent and I both tried independently with Agda, but even with dependent types we got stuck. But that doesn't stop you using the paper to hand craft the appropriate type. (I guess Template Haskell would work fine but that's cheating.)
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Very nice paper!
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Unfortunately, 'cum laude' differs highly per country. E.g. in The Netherlands 'cum laude' is the only distinction and is awarded to ~5-10% of PhDs. Germany follows the usual three distinctions of the Latin system (cum laude, magna cum laude, summa cum laude). tl;dr: in The Netherlands cum laude is the highest distinction, in Germany summa is the highest distinction and you probably want to get at least cum laude.

Though, I am not sure if this applies to 'with honours' to, if it is less ambiguous, that would be something :).
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Noah's favorite game right now is to sing "A,B,C,D,E,F,____" where the __ is filled in with anything other than "G" (e.g. "Q", but more often non-letters such as "cow", "lobster", "seven", "climb").  Whereupon I tickle him in mock outrage and he shrieks with laughter.  I'm very proud that my son finds type errors humorous.
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Teach him 123456789ABCDEF0.
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Have him in circles
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Currently
Conway, AR
Previously
Philadelphia, PA - Washington, DC - Williamstown, MA
Work
Occupation
Professor
Employment
  • University of Pennsylvania
    PhD student, 2007 - 2013
  • Williams College
    Visiting Assistant Professor , 2013 - 2014
  • Hendrix College
    Assistant Professor, 2014 - present
Education
  • Williams College
    Computer Science, 1999 - 2003
  • University of Pennsylvania
    Computer Science, 2007 - 2013
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Gender
Male
Birthday
January 10
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Married
Public - 3 months ago
reviewed 3 months ago
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