410 index index.xml Justine Frank Justine Frank false Hi! I am Justine Frank, I am currently in my 5th year as a Ph.D. student in the PLUM Lab at the University of Maryland College Park. I am trying to find better ways to prove the correctness of programming language implementations, especially type systems and compilers. Working with Milijana Surbatovich and Leonidas Lampropoulos. My CV can be found here. In my free time I like to rock climb, bike, and occasionally build mechanical keyboards. I have a very sparse blog. 412 jpf-contact jpf-contact.xml Contact Info Justine Frank email: jpfrank [at] umd [dot] edu github: laelath orcid: 0009-0007-7024-7331 mastodon: justinefrank@types.pl 414 jpf-pubs jpf-pubs.xml Publications Bibliography Justine Frank 336 #241 unstable-241.xml Accepted papers Justine Frank false 338 frank-quiring-lampropoulos-2024 frank-quiring-lampropoulos-2024.xml Generating Well-Typed Terms That Are Not “Useless” Reference 2024 1 5 Justine Frank Benjamin Quiring Leonidas Lampropolous 10.1145/3632919 POPL ’24: 51st ACM SIGPLAN Symposium on Principles of Programming Languages https://youtu.be/KkE-wVqUbVQ Random generation of well-typed terms lies at the core of effective random testing of compilers for functional languages. Existing techniques have had success following a top-down type-oriented approach to generation that makes choices locally, which suffers from an inherent limitation: the type of an expression is often generated independently from the expression itself. Such generation frequently yields functions with argument types that cannot be used to produce a result in a meaningful way, leaving those arguments unused. Such "use-less" functions can hinder both performance, as the argument generation code is dead but still needs to be compiled, and effectiveness, as a lot of interesting optimizations are tested less frequently. In this paper, we introduce a novel algorithm that is significantly more effective at generating functions that use their arguments. We formalize both the "local" and the "nonlocal" algorithms as step-relations in an extension of the simply-typed lambda calculus with type and arguments holes, showing how delaying the generation of types for subexpressions by allowing nonlocal generation steps leads to "useful" functions. 342 geller-frank-bowman-2024 geller-frank-bowman-2024.xml Indexed Types for a Statically Safe WebAssembly Reference 2024 1 5 Adam T. Geller Justine Frank William J. Bowman 10.1145/3632922 POPL ’24: 51st ACM SIGPLAN Symposium on Principles of Programming Languages https://youtu.be/mkTgnFrv7lI We present Wasm-prechk, a superset of WebAssembly (Wasm) that uses indexed types to express and check simple constraints over program values. This additional static reasoning enables safely removing dynamic safety checks from Wasm, such as memory bounds checks. We implement Wasm-prechk as an extension of the Wasmtime compiler and runtime, evaluate the run-time and compile-time performance of Wasm-prechk vs WebAssembly configurations with explicit dynamic checks, and find an average run-time performance gain of 1.71x faster in the widely used PolyBenchC benchmark suite, for a small overhead in binary size (7.18% larger) and type-checking time (1.4% slower). We also prove type and memory safety of Wasm-prechk, prove Wasm safely embeds into Wasm-prechk ensuring backwards compatibility, prove Wasm-prechk type-erases to Wasm, and discuss design and implementation trade-offs. 346 #242 unstable-242.xml Presentations Justine Frank false 348 frank-njpls-2025-05 frank-njpls-2025-05.xml Indistinguishability Reasoning for Interaction Trees Reference 2025 5 9 Justine Frank njpls-tutt-slides.pdf NJPLS May'25: New Jersey Programming Languages and Systems Seminar Interaction trees are an increasingly popular way to define and reason about the semantics of non-terminating, effectful, first-order programming languages using layered monadic interpreters. They have a rich equational theory for reasoning up to strong- or weak-bisimulation. However, for some applications, like crash recovery systems, bisimulation is too strong; the desired property is not that two computations behave the same, but that they will be indistinguishable---they will never be observed behaving differently. To enable reasoning about indistinguishability, we develop tolerance-up-to-taus (tutt); an extension of equivalence-up-to-taus (eutt) that allows removing an infinite number of taus from either side. We draw out the insight that the tutt relation thus has a nice property of being a middle point in between termination-sensitive and termination-insensitive reasoning, permitting reasoning about computations that do not terminate yet continuously perform observable effects. A key challenge of working with tutt is that, unlike eutt, this relation does not admit transitivity; however, we show that it is compatible with existing ITree "up-to" reasoning, allowing rewriting by bisimulation equivalences while proving tutt, and supports reasoning up-to bind. Finally, we showcase the usefulness of tutt by demonstrating a proof of indistinguishability of crash-recovering executions of a program. 416 jpf-events jpf-events.xml Attendances Justine Frank 314 #251 unstable-251.xml Conferences Justine Frank 316 popl-2024 popl-2024.xml POPL ’24: 51st ACM SIGPLAN Symposium on Principles of Programming Languages Conference 2024 1 https://popl24.sigplan.org/ The annual Symposium on Principles of Programming Languages is a forum for the discussion of all aspects of programming languages and programming systems. Both theoretical and experimental papers are welcome on topics ranging from formal frameworks to experience reports. We seek submissions that make principled, enduring contributions to the theory, design, understanding, implementation, or application of programming languages. 317 icfp-2023 icfp-2023.xml ICFP ’23: 28th ACM SIGPLAN International Conference on Functional Programming Conference 2023 9 https://icfp23.sigplan.org/ 318 popl-2023 popl-2023.xml POPL ’23: 50th ACM SIGPLAN Symposium on Principles of Programming Languages Conference 2023 1 https://popl23.sigplan.org/ The annual Symposium on Principles of Programming Languages is a forum for the discussion of all aspects of programming languages and programming systems. Both theoretical and experimental papers are welcome on topics ranging from formal frameworks to experience reports. We seek submissions that make principled, enduring contributions to the theory, design, understanding, implementation or application of programming languages. 319 #252 unstable-252.xml Summer Schools Justine Frank 321 oplss-2024 oplss-2024.xml OPLSS ’24: Oregon Programming Languages Summer School 2024 2024 6 https://www.cs.uoregon.edu/research/summerschool/summer24/ The Oregon Programming Languages Summer School has been devoted for twenty years to teaching the principles of programming languages to students and professionals. Although the topics vary from year to year, the unifying theme is the importance of fundamental theory to the design and implementation of programming languages, the development of program verification tools, and the application of advanced programming languages to practice. The program takes place over two weeks, with ample time for group and private study. The summer school attracts participants from around the world, and is often able to subsidize the participation of qualified attendees with limited resources. More than a thousand participants have attended OPLSS since its inception in 2002. The summerschool is sponsored by generous grants from numerous companies. 322 oplss-2022 oplss-2022.xml OPLSS ’22: Oregon Programming Languages Summer School 2022 2022 6 https://www.cs.uoregon.edu/research/summerschool/summer22/ The Oregon Programming Languages Summer School has been devoted for twenty years to teaching the principles of programming languages to students and professionals. Although the topics vary from year to year, the unifying theme is the importance of fundamental theory to the design and implementation of programming languages, the development of program verification tools, and the application of advanced programming languages to practice. The summer school attracts participants from around the world, and is often able to subsidize the participation of qualified attendees with limited resources. More than a thousand participants have attended OPLSS since its inception in 2002. The summer school is sponsored by the National Science Foundation, and by generous grants from numerous companies over the years. 323 #253 unstable-253.xml Seminars Justine Frank 325 njpls-12-2025 njpls-12-2025.xml NJPLS Dec'25: New Jersey Programming Languages and Systems Seminar Seminar 2025 12 5 https://njpls.org/dec2025.html 326 njpls-05-2025 njpls-05-2025.xml NJPLS May'25: New Jersey Programming Languages and Systems Seminar Seminar 2024 5 9 https://njpls.org/may2025.html 327 njpls-12-2024 njpls-12-2024.xml NJPLS Dec'24: New Jersey Programming Languages and Systems Seminar Seminar 2024 12 6 https://njpls.org/dec2024.html 328 njpls-05-2024 njpls-05-2024.xml NJPLS May'24: New Jersey Programming Languages and Systems Seminar Seminar 2024 5 10 https://njpls.org/may2024.html 329 njpls-11-2023 njpls-11-2023.xml NJPLS Nov'23: New Jersey Programming Languages and Systems Seminar Seminar 2023 11 10 https://njpls.org/nov2023.html 330 njpls-05-2023 njpls-05-2023.xml NJPLS May'23: New Jersey Programming Languages and Systems Seminar Seminar 2023 5 19 https://njpls.org/may2023.html 331 njpls-10-2022 njpls-10-2022.xml NJPLS Oct'22: New Jersey Programming Languages and Systems Seminar Seminar 2022 10 22 https://njpls.org/oct22.html If you recognize me from any of these events and want to chat please reach out! Related 418 jpf-blog jpf-blog.xml Blog Justine Frank 289 JPF-0001 JPF-0001.xml Getting FFS Post 2026 1 28 Justine Frank I got facial feminization surgery (FFS) in the late summer of last year. For me this consisted of five procedures, a type III brow ridge reduction by a coronal incision (I have titanium in my skull now!), a brow lift that is apparently standard when doing a brow ridge reduction, rhinoplasty (nose), mandible contouring (jaw), and tracheal shave (Adam's apple). The recovery process has been one of the most intense things I have gone through in my life, both emotionally and physically. There are many aspects about getting FFS that have been shared online, from the highs of people getting beautiful results mere weeks after surgery, to horror stories of bad recoveries and rude doctors. But I wanted to share some of my own more closer to average experiences with FFS, and some of the hardships that I felt the most pressing and less talked about, or at least not talked about enough relative to how important I felt they were to my experience. 261 #243 unstable-243.xml You need someone to help you recover 2026 1 28 Justine Frank The most important piece of advice I can give is to have people who are able to help with the recovery process for the first two weeks. That includes helping with wound care, food preparation, and just being there with you. The main wound care concern I had was needing to clean my coronal incision twice a day, and wash my hair once a day. This might not sound so bad, but the amount of fatigue I was experiencing made it very hard to hold my arms up over my head for more than a few seconds. On top of that, waves of more intense fatigue would hit periodically that would take me from feeling fairly normal, to having any effort, including what it takes to stand, feel unimaginably hard. Washing my hair couldn't be done the normal way either, I had to flip my hair forwards, and be very careful to only push towards the incision, holding either my forehead or scalp in place with my other hand, as to not pull the incision apart. For the first few days this was accomplished mostly by me sitting in the shower on a chair, holding up my forehead as a friend very carefully rubbing shampoo in. As I slowly gained more energy I was able to do more parts of the process myself. It might seem like too small a task to ask a friend to throw some ingredients into a blender for you, but when you are going through intense fatigue the prospect of having to walk from your bed to the fridge, grab all the ingredients, carry them upstairs to where the blender is, make the smoothie, and then clean the blender, feels closer to running a marathon except that if you collapse halfway you also starve. I cannot imagine being able to carry out my own wound care and prepare my own food during this period by myself, do not try to go through it alone. 263 #244 unstable-244.xml Buy liquid meals beforehand 2026 1 28 Justine Frank Soylent saved my life. While I was allowed to eat solid food as long as it was soft enough to not poke the sutures in my mouth, chewing food with a swollen jaw, a throat irritated from having a breathing tube shoved down it for six hours, while being nauseous from the anesthesia and painkillers is not something I personally recommend. Chewing itself also felt physically exhausting for the first week or so, I simply would not have gotten enough to eat if I wasn't drinking my meals. That plus the fatigue means having an always-ready easy-to-consume source of food is invaluable. 265 #245 unstable-245.xml Your feelings about your face will fluctuate dramatically 2026 1 28 Justine Frank When I came to after surgery I felt an immense feeling of relief and peace. My face was entirely wrapped in bandages, only my eyes and mouth were visible. My mouth had many stiches in it that poked at my mouth. I felt an immense amount of pain. But over that, I could feel the bandages laying flat against my forehead. I felt the bandages around my chin forming a smooth "U" instead of bulging around the prominent bumps that had made me self conscious for so many years. When I was able to unwrap my face, it looked rough. There were large yellow bags under both of my eyes, above my eyes was deeply bruised almost like I had put on too much eyeliner. My jaw looked like a dog that found a wasps nest. It was easy to look just at features like the smoothness of my forehead and be thrilled, even amoung the uncertainty that I had about what my face would eventually look like. As the swelling went down and the bruises faded, my face turned from an obviously puffy mess into something that looked a lot more like a real face. I went from looking at the specific features I could tell had been improved, to nitpicking the overall impression that I felt my face now had. A fun quirk about swelling in your face is that it goes down roughly top to bottom. That is, first the swelling in your forehead goes down, then around your eyes, then your cheeks, and finally around your chin. Apparently this is literally because gravity is helping the fluids drain downwards to pool in your chin. So, when I first started seeing my face as one that looked normal and was not obviously massively injured, I saw this swelling filling my chin back close to my original jaw line. I saw that my Adam's apple still formed a noticable bump, I saw my deep set eyes under overhead lighting mimicking the brow ridge I had hated so much. I didn't see that no one sees your face from the worst possible angles under the worst possible lighting, that my Adam's apple was much less prominent than it was before, that no one sees your face exclusively from your worst angles, or how much swelling was still left and how much better it would still get. This initial impression caused a fair amount of spiraling about whether or not it had really been worth it, whether I could really hope to one day have a face that I didn't cringe at every time I saw it. I found that the easiest way to alleviate these feelings was to look at the pictures I had of my face before, which made it pretty clear how worth it it was. 267 #246 unstable-246.xml Not everyone will notice 2026 1 28 Justine Frank And that is not a commentary on the effectivness of your results! This one was actually in the recovery packet my surgeon gave me, but since I didn't believe it there I wanted to say here that it was 100 percent true. Changing your face is almost like an experiment in what the people around you recognize you by. I have walked right up to friends who did not recognize me until I spoke, and had faimly members who I saw regularly most of my life not realize that anything had changed until I told them. There are a million tiny different things that people use to recognize who you are, and you get a chance at messing with one of them and seeing how everyone around you reacts. Interestingly the people who where the least likely to notice were coworkers or other people who I see often but am not that close to. I think there is also an effect where, once people recognize you, if they aren't specifically looking for differences, they just update their mental model of what you look like to what they see in front of them. It probably also helps that even if they feel something looks a bit different, it probably won't occur to them that it was your face that changed. 269 #247 unstable-247.xml Getting misgendered can hurt more 2026 1 28 Justine Frank Before getting FFS I really didn't think that much about getting misgendered, I guess I was somewhat numb to it. Since getting FFS I have been gendered correctly vastly more frequently than before. However, the pain and intensity of recovery creep in to the situations where I am. I have been told this will fade with time as the memories of the recovery period become less fresh. 271 #248 unstable-248.xml Be mentally prepared for the healing to not go perfectly smoothly 2026 1 28 Justine Frank Having complications, no matter how minor, during healing will hit your anxiety extra hard because, well, it is your face. It can be really hard to not obsess over whether doing something slightly wrong will result in a scar being more prominent, your nose being forever crooked. This is not helped by needing to follow wound care instructions that directly tell you that messing it up can lead to wider scars or that certain massages are in part to ensure things end up symmetric. If you feel something is going wrong let your surgeon know what is happening and try to not panic as long as they aren't. 273 #249 unstable-249.xml Do not try to rush getting back to work 2026 1 28 Justine Frank I tried to. I pushed myself to rush back to work to meet a deadline that was only a few weeks after my surgery. Do not do this. 275 #250 unstable-250.xml Where I am at now 2026 1 28 Justine Frank Getting FFS was probably the second best decision I have made in my life after starting HRT. It has helped me to be immensely more confident and comfortable in my gender expression. Looking in the mirror and seeing someone who actually feels like yourself is worth more than I know how to properly express. If you are at all considering getting it and have money and/or insurance, start scheduling consultations right now. It is a process that you can call off or delay whenever you want, but one that cannot be sped up. I was extremely lucky to be able to go from seeking a consultation to getting surgery in about eight months. If you are considering getting FFS and want to ask someone who has gone through the process any questions, please reach out to me! 420 justinefrank justinefrank.xml Justine Frank Person https://laelath.github.io/ Programming Languages at University of Maryland 0009-0007-7024-7331 PhD Student PhD Student in Programming Languages and Formal Verification in my 4th year at the University of Maryland College Park. Working with Leonidas Lampropolous and Milijana Surbatovich. In 2020 I obtained a bachelor of science in computer science from the University of British Columbia, and worked with the SPL until starting with PLUM in fall 2021.