Colm Mulcahy

Colm Mulcahy

@cardcolm.bsky.social

Prof Emeritus Spelman College, Adjunct Prof SETU, Ireland. Board Gathering 4 Gardner. Curator Annals of Irish Maths. Author "Mathematical Card Magic" AKP/CRC Press

593 followers392 following1.9K posts

Colm Mulcahy reposted

Ivy Cummings claimed that in 1913 age 11 she was youngest person to lap @ Brooklands in her dad's car when he wasn't looking. Grew up to be successful racing driver, ran garage in 1920s on #Putney Bridge Road where repaired & sold cars. b. #OTD 27 Oct 1901 en.wikipedia.org/wiki/Ivy_Cum...

Colm Mulcahy reposted

Absolutely brilliant to see. Yet fossil fuel use and emissions are STILL increasing, because capitalist economies require endless growth. On a finite planet, that can only end one way. Without system change, much of our efforts are little more than rearranging deck chairs on the Titanic.

Jan Rosenow@janrosenow.bsky.social

Solar has overtaken nuclear. A decade ago it supplied 1% of the world's power. In 2025 it met three quarters of global demand growth. Almost nobody saw it coming. I spoke to Jocelyn Timperley at BBC Future about why. www.bbc.co.uk/future/artic...

Picture sleeves were only starting to appear in the UK then. Penny Lane/Strawberry Fields Forever two months later was the first I recall.

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Colm Mulcahy reposted

just heartbreaking stuff Alex Pretti's mother calls out ICE and the Trump administration for killing her son and smearing his name, and calls for justice to be done.

Colm Mulcahy reposted

Replying to @miaganga.bsky.social

I am not certain all the fishermen they killed at sea were running drugs either. IMO that is straight up murder

Colm Mulcahy reposted

Come along to not one, but two history seminars this week. First up we have Dr John Regan (University of Dundee) who is speaking on 'Sir John Temple (1600-77), and the historiography of the Irish rebellion (c. 1917-23)', Wednesday 28 October at 2.30pm in the Bridge Room, Hardiman Research Building.

Colm Mulcahy reposted

Michael Atiyah ๐Ÿ‡ช๐Ÿ‡ฌ: Fields Medal 1966 (also Abel Prize 2004), for K-theory. Ahmed Zewail ๐Ÿ‡ช๐Ÿ‡ฌ: Nobel for Chemistry 1999, for his work on femtochemistry. Omar M. Yaghi ๐Ÿ‡ฏ๐Ÿ‡ด: Wolf Prize 2018, Nobel for Chemistry 2025, for his work on reticular chemistry Naguib Mahfouz ๐Ÿ‡ช๐Ÿ‡ฌ: Nobel for literature 1988

The Bulwark@thebulwark.com

RFK: "There's five hundred million Arabs in the world. And yet they don't produce science. They don't win the Nobel Prize. They don't win the Fields Prize. They don't win the Wolf Prize. They don't produce literature."

Colm Mulcahy reposted

Colm Mulcahy reposted

Not drawn to (time) scale. Ireland, Britain and a Europe were connected at that stage.

Massimo (mirror)@rainmaker1973-m.bsky.social

One pretty cool geological fun fact is that the Appalachian Mountains, the Atlas Mountains, the Scottish Highlands, the Watkins Range and Scandinavian Mountains were all once part of the same mountain range, the Central Pangean Mountains. Original post

Colm Mulcahy reposted

Looking for a new high horse from which I can radiate smug disdain on social media. Anyone have recommendations? I'd hate to miss out on this highly valuable activity.

Colm Mulcahy reposted

Here's a slice of Young's lattice โ€” integer partitions with at most m pieces each of size at most n โ€” as a little Sunday treat: e-infinity.space/young-lattice/ It's built as the quotient of the Boolean lattice Bโ‚˜โ‚™ by the action of ๐”–โ‚˜โ‰€๐”–โ‚™ โ‰ค ๐”–โ‚˜โ‚™. ๐Ÿงฎ

Colm Mulcahy reposted

Replying to @e-infinity.space

For me, the most compelling open triangle is tomato / lime / cottage cheese. tomato + lime = salsa tomato + cottage cheese = budget Caprese salad lime + cottage cheese = Grandma's lime jello salad tomato + lime + cottage cheese: get the fuck out of here.

Colm Mulcahy reposted

I just analyzed 1.9M recipes and can now report that the yummy simplicial complex is arguably *not* flag. The following flavor trios have far fewer recipes containing all three ingredients than the recipes with pairs of ingredients would predict.

An open problem in culinary mathematics: Consider the ๐‘ฆ๐‘ข๐‘š๐‘š๐‘ฆ ๐‘ ๐‘–๐‘š๐‘๐‘™๐‘–๐‘๐‘–๐‘Ž๐‘™ ๐‘๐‘œ๐‘š๐‘๐‘™๐‘’๐‘ฅ Y on vertex set I = {ingredients} where ฯƒโˆˆY iff the ingredients in ฯƒ appear in a single good recipe. Question: Is Y a flag simplicial complex? (A complex Y is ๐‘“๐‘™๐‘Ž๐‘” when ฯƒโˆˆY iff {x,y}โˆˆY for all x,yโˆˆฯƒ.)