单纯二重有向三元系的相交数

Intersections of Simple Directed Triple Systems with λ =2

解决了单纯二重有向三元系的相交数问题．即证明了对于任一正整数ｖ≥３，ｖ≡０，１（ｍｏｄ３），存在两个单纯二重有向三元系相交于ｓ个公共区组的充要条件是：当ｖ≥４时，ｓ∈｛０，１，２，…，２ｖ（ｖ－１）／３｝，ｓ≠［２ｖ（ｖ－１）／３］－１；当ｖ＝３时，ｓ∈｛０，２，４｝．

The intersection problem of simple directed triple systems with λ =2 is completely solved, namely, it is proved that for v ≡0,1 (mod 3), v ≥3,there exist two simple DTS( v ,2)s intersecting in s triple if and only if, s∈{0,1,2,…,2v(v-1)/3},s≠[2v(v-1)/3]-1, while v≥4 s∈{0,2,4},while v=3