Polar Graphs and Corresponding Involution Sets, Loops and Steiner Triple Systems |
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Authors: | Helmut Karzel Silvia Pianta Elena Zizioli |
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Institution: | (1) Zentrum Mathematik, T.U. München, D-80290 München, Germany;(2) Dipartimento di Matematica e Fisica, Università Cattolica, Via Trieste, 17, I-25121 Brescia, Italy;(3) Dipartimento di Matematica, Facoltà di Ingegneria, Università degli Studi di Brescia, Via Valotti, 9, I-25133 Brescia, Italy |
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Abstract: | A 1-factorization (or parallelism) of the complete graph with loops
is called polar if each 1-factor (parallel class) contains exactly one loop and for any three distinct vertices x1, x2, x3, if {x1} and {x2, x3} belong to a 1-factor then the same holds for any permutation of the set {1, 2, 3}. To a polar graph
there corresponds a polar involution set
, an idempotent totally symmetric quasigroup (P, *), a commutative, weak inverse property loop (P, + ) of exponent 3 and a Steiner triple system
.
We have:
satisfies the trapezium axiom
is self-distributive ⇔ (P, + ) is a Moufang loop
is an affine triple system; and:
satisfies the quadrangle axiom
is a group
is an affine space. |
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Keywords: | 20N05 05C70 51E10 |
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