What do these symbols mean? One looks like an inverse "T", another looks like ^

1k Views Asked by Bumbble Comm At 03 Apr 2026 - 9:28

I saw an equation as the following one. enter image description here

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The following is the context: enter image description here

This is the source:

On Updating Problems in Latent Semantic Indexing, SIAM Journal on Scientific Computing - 21(2):pp. 782-791;