4 citations · 9 across the 8 of their papers we have counts for
8 papers
On nontrivial cross-2-intersecting families
Jingjun Bao, Lijun Ji, Liying Yu
Two families \(\mathcal{A}\subseteq\binom{[n]}{k}\) and \(\mathcal{B}\subseteq\binom{[n]}{\ell}\) are said to be nontrivial cross-\(t\)-intersecting if \(|A \cap B| \geq t\) for al…
The maximum product of sizes of cross-\(t\)-intersecting families
Jingjun Bao, Lijun Ji
Two families of sets \(\mathcal{A}\) and \(\mathcal{B}\) are called \emph{cross-\(t\)-intersecting} if \(|A \cap B| \geq t\) for all \(A \in \mathcal{A}\) and \(B \in \mathcal{B}\)…
New Necessary Conditions for Existence of Strong External Difference Families
Jingjun Bao, Lijun Ji
Strong external difference families (SEDFs) were introduced by Paterson and Stinson as a more restrictive version of external difference families. SEDFs can be used to produce opti…
New Existence and Nonexistence Results for Strong External Difference Families
Jingjun Bao, Lijun Ji, Ruizhong Wei +1
In this paper, we use character-theoretic techniques to give new nonexistence results for -strong external difference families (SEDFs). We also use cyclotomic classes to…
New families of Strictly optimal Frequency hopping sequence sets
Jingjun Bao
Frequency hopping sequences (FHSs) with favorable partial Hamming correlation properties have important applications in many synchronization and multiple-access systems. In this pa…
Frequency hopping sequences with optimal partial Hamming correlation
Jingjun Bao, Lijun Ji
Frequency hopping sequences (FHSs) with favorable partial Hamming correlation properties have important applications in many synchronization and multiple-access systems. In this pa…
New families of optimal frequency hopping sequence sets
Jingjun Bao, Lijun Ji
Frequency hopping sequences (FHSs) are employed to mitigate the interferences caused by the hits of frequencies in frequency hopping spread spectrum systems. In this paper, we pres…
The completion of optimal -packings
Jingjun Bao, Lijun Ji
A 3- packing design consists of an -element set and a collection of -element subsets of , called {\it blocks}, such that every -element subset of is co…