#topology — Public Fediverse posts
Live and recent posts from across the Fediverse tagged #topology, aggregated by home.social.
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I'm Anthony, a #math phd candidate at George Mason University! I like to think about stochastic #topology, #probability, random #algorithms, and quantitative justice. let me know if you're going to the AMS Eastern Sectional at GWU in October, I'd love to say hi :)
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River Network Routing And Discharge Partitioning On A Multichannel River Network
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https://doi.org/10.1029/2025WR041417 <-- shared paper
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"... KEY POINTS:
• River multifurcation pathways were identified in a vector river network globally
• A multifurcation scheme was added to a river network routing model to split river discharge at divergences
• Accounting for multichannels improved discharge accuracy and resulted in earlier arrival of flood waves downstream of divergences…”
#GIS #spatial #mapping #spatialanalysis #spatiotemporal #model #modeling #water #hydrology #river #stream #watercourse #floods #flooding #risk #hazard #benefit #network #segment #downstream #upstream #braiding #sinuosity #delta #complexity #flowdirection #remotesensing #confluence #bifurcations #divergence #multifurcation #discharge #topology #routing #global #landsurface #Pfafstetter #basin -
The name for the algebraic structure consisting of a set \(A\) equipped with a binary operation \(f\colon A^2\to A\) which is not assumed to be commutative, associative, etc. has an interesting history. As far as I can tell, this sort of algebra was originally known as a "groupoid", and you can find recent literature using the term in that way. However, Nicolas Bourbaki called a set with a single binary operation a "magma" in his Éléments de mathématique and this name came to be used when there might be confusion with the newer topological use of "groupoid" to mean a category whose morphisms are all invertible. A third contender is "binar". I don't know the history of this one but it seems reasonable to me.
I prefer "magma" myself. I don't know what a "lava" or a "volcano" should be nor have I had the audacity to try to name something like this in the literature. One reason I prefer "magma" is that I can talk about a set \(A\) equipped with a single \(n\)-ary operation \(f\colon A^n\to A\) as an "\(n\)-ary magma" (or just "\(n\)-magma" or even "magma").