When a prime divides the elliptic discriminant of a elliptic curve , two or all three roots of become congruent (mod ). An elliptic curve is semistable if, for all such primes , only two roots become congruent mod (with more complicated definitions for or 3).
Semistable
See also
Elliptic Curve, Elliptic DiscriminantExplore with Wolfram|Alpha
Cite this as:
Weisstein, Eric W. "Semistable." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/Semistable.html