Mex
The Minimum excluded value. The mex of a Set 
of Nonnegative Integers is theleast Nonnegative Integer not in the set.
References
Guy, R. K. ``Max and Mex Sequences.'' §E27 in Unsolved Problems in Number Theory, 2nd ed. New York: Springer-Verlag, pp. 227-228, 1994.
- T-Polyomino
- T-Puzzle
- Trace (Complex)
- Trace (Group)
- Trace (Map)
- Trace (Matrix)
- Trace (Tensor)
- Tractory
- Tractrix
- Tractrix Evolute
- Tractrix Radial Curve
- Tractroid
- Transcendental Curve
- Transcendental Equation
- Transcendental Function
- Transcendental Number
- Transcritical Bifurcation
- Transfer Function
- Convergent Sequence
- Convergent Series
- Conversion Period
- Convex
- Convex Function
- Convex Hull
- Convex Optimization Theory