The Erdős unit distance problem asks how many pairs of points can sit exactly one unit apart. Paul Erdős guessed the answer in 1946, and the guess stood for eighty years. In May 2026, an OpenAI model found a counterexample. I checked the grid trick behind it in SQL Server, spatial queries included.
Navier-Stokes Problem: What It Is and What AI Found
The Navier-Stokes problem in plain words: what the famous fluid question asks, what AI says it found, and why it is not official yet.
Fermat Left a Note in a Margin. Other People Spent 358 Years Finishing It.
That note kept mathematicians busy for the next three and a half centuries. Let us talk about what Fermat left in a margine.
A Simple Linear Regression Trend Line in T-SQL
Calculate linear regression slope, intercept, monthly predictions, and R-squared in T-SQL while keeping extrapolation limits clear.
Loan Amortization Schedules With a Recursive CTE
Why does the last loan payment leave a few cents behind? A recursive CTE, a rounding rule and a final reconciliation fix it.
Median on Big Tables: PERCENTILE_CONT vs a Two-Row Seek
Two ways to get a median, one tiny demo, and the traps in NULLs, even counts and empty tables. Then measure on your own server.
Cosine, Euclidean or Dot: Picking a Vector Distance Metric
Cosine, Euclidean and dot can rank the same vectors differently. Here are tiny examples you can check by hand, plus how to choose.