Quasigroup
A Groupoid 
such that for all 
, there exist unique 
such that
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No other restrictions are applied; thus a quasigroup need not have an Identity Element, not be associative, etc.Quasigroups are precisely Groupoids whose multiplication tables are Latin Squares.A quasigroup can be empty.See also Binary Operator, Groupoid, Latin Square, Loop (Algebra), Monoid, Semigroup
References
van Lint, J. H. and Wilson, R. M. A Course in Combinatorics. New York: Cambridge University Press, 1992.
- Ordinary Differential Equation
- Ordinary Differential Equation--First-Order
- Ordinary Differential Equation--First-Order Exact
- Ordinary Differential Equation Second-Order
- Ordinary Differential Equation--System with Constant Coefficients
- Ordinary Double Point
- Ordinary Line
- Ordinary Point
- Ordinate
- Ore Number
- Ore's Conjecture
- Ore's Theorem
- Orientable Surface
- Orientation (Plane Curve)
- Orientation-Preserving
- Orientation-Reversing
- Orientation (Vectors)
- Origami
- Origin
- Ornstein's Theorem
- Orr's Theorem
- Orthic Triangle
- Orthobicupola
- Orthobirotunda
- Orthocenter