Ron Garcia
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rg9119.bsky.social
Ron Garcia
@rg9119.bsky.social
630 followers 190 following 160 posts
Transmogrifying coffee into LaTeX, but now more grumpy and slow about it. University of British Columbia Computer Science
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rg9119.bsky.social
I got a good chuckle out of this rather formal rant about difficulty the other week:

(FWIW I've often heard (and agree) that the hardest problem in computer science is naming things, so pretty sure we suck just as much!)
An excerpt from McDonald's "Test Theory" book where he grouses about the term "difficulty".
November 7, 2025 at 6:21 PM
rg9119.bsky.social
Recently I learned that sometimes the axioms aren't enough 😢

(from "When is conditional probability meaningful?" in arxiv.org/pdf/1802.06071)
Some gnarly example due to Lévy, where conditional probability according to Kolmogorov's axioms gives answers that make no one happy.
August 27, 2025 at 6:51 PM
rg9119.bsky.social
Not a bad way to celebrate Canada Day: by updating my cv 🤗🇨🇦
Added my transition to Full Professor effective today, woohoo!
July 2, 2025 at 12:10 AM
rg9119.bsky.social
checks out
Text from the wikipedia page for Peter Carl Fabergé: "His time in Europe had inspired him to make pieces that were more than a sum of their parts. As he later described in his own words: "Expensive things interest me little if the value is merely in so many diamonds or pearls"."
June 29, 2025 at 5:39 PM
rg9119.bsky.social
Counterpoint:
June 18, 2025 at 9:35 PM
rg9119.bsky.social
All my feelings about floating point numbers, distilled into two pictures:
A still from the talk "Theories, Solvers and Static Analysis by Abstract Interpretation" demonstrating a loop that converges to 6 for exact reals and converges to 100 for any finite precision An image of Racket code demonstrating a loop that converges as described in the previous picture
May 18, 2025 at 11:34 PM
rg9119.bsky.social
I am firmly on team Henri Lebesgue:
mathshistory.st-andrews.ac.uk/Biographies/...
text: "Mathematicians have never been in full agreement on their science, though it is said to be the science of self-evident verities -- absolute, indisputable and definitive. They have always been in controversy over developing aspects of mathematics, and they have always considered their own age to be in a period of crisis."
April 30, 2025 at 7:00 PM
rg9119.bsky.social
maybe this is devil's advocate's devil's advocate, but, evoking John Regehr, it might be the case that in the year twenty twenty-five, because of changes in the language semantics, C23 (as opposed to C89) may be the wrong substrate with which to teach about low-level systems abstractions.
text from a recent mastodon post about a textbook on computer systems that continues to treat C (incorrectly) as portable assembly language.
January 19, 2025 at 5:01 AM
rg9119.bsky.social
Fun fact: according to L.J. Savage, R.A. Fisher did not subscribe to that interpretation:
projecteuclid.org/journals/ann...
Excerpt from linked paper: "What is probability? Fisher, as everybody knows, was a frequentist, yet I-who profess to interest in such things-was somewhat taken aback in my rereading to find how vehemently he denies that probability is a limiting frequency in an indefinite sequence of repeated 1actuall trials, which is the position that frequentists ordinarily take 24 (1935b 81; 1958a; 1960 5-7; SI 109-10; see also 1922a 312-3; 1925a 700-1; DOE§§ 3, 6; SI 14, 32-3, 44, 114-6). For Fisher, a probability is the fraction of a set, having no distinguishable subsets, that satisfies a given condition (SI 32-3, 55-7, 109-10; 1958a; 1960 5-6; see also 1922a 312-3; 1925a 700-1; 1935b 78; 1945b 129; 1955 75; 1961a 3, 7). For example, in showing the cards of a well-shuffled deck one at a time, exactly one-quarter of the showings will result in hearts-there can be no question about that. And there are no distinguishable subsets; that means that no particular subset of showings, such as the first thirteen or either of the alternate sets of twenty-six, can be expected to be richer in hearts than others. This is a notion that not everyone will find clear and acceptable, but let us at least allow Fisher to describe it in his own terms:"
December 6, 2024 at 7:42 PM
rg9119.bsky.social
btw I get this from Alfred North Whitehead's Introduction to Mathematics (an excellent text).
"...and 3x + 2y − 5 = 0 represents another definite correlation between the variables x and y; and both correlations have the form of what we have called linear correlations. But now, how can we represent any linear correlation between the variable numbers x and y? Here we want to symbolize any linear correlation; just as x symbolizes any number. This is done by turning the numbers which occur in the definite correlation 3x + 2y −5 = 0 into letters. We obtain ax + by − c = 0. Here a, b, c, stand for variable numbers just as do x and y: but there is a difference in the use of the two sets of variables. We study the general properties of the relationship between x and y while a, b, and c have unchanged values. We do not determine what the values of a, b, and c are; but whatever they are, they remain fixed while we study the relation between the variables x and y for the whole group of possible values of x and y. But when we have obtained the properties of thiscorrelation, we note that, because a, b, and c have not in fact been determined, we have proved properties which must belong to any such relation. Thus, by now varying a, b, and c, we arrive at the idea that ax+by −c = 0 represents a variable linear correlation between x and y. In comparison with x and y, the three variables a, b, and c are called constants. Variables used in this way are sometimes also called parameters. Now, mathematicians habitually save the trouble of explaining which of their variables are to be treated as “constants,” and which as variables, considered as correlated in their equations, by using letters at the end of the alphabet for the “variable” variables, and letters at the beginning of the alphabet for the “constant” variables, or parameters. ... Sometimes a word or two of explanation is necessary; but as a matter of fact custom and common sense are usually sufficient, and surprisingly little confusion is caused by a procedure which seems so lax.
October 21, 2024 at 1:49 AM
rg9119.bsky.social
This little vignette from Scott Page's The Model Thinker really struck me when I first read it:
Excerpt from Scott E. Page's The Model Thinker, screenshot from: https://www.google.ca/books/edition/The_Model_Thinker/iWRPDwAAQBAJ?hl=en&gbpv=1&dq=Scott+E.+Page+BMI&pg=PT63&printsec=frontcover
November 27, 2023 at 7:49 PM
rg9119.bsky.social
Current status of the outlet:
October 31, 2023 at 3:32 PM