Saxl Conjecture for triple hooks

We make some progresses on Saxl conjecture. Firstly, we show that the probability that a partition is comparable in dominance order to the staircase partition tends to zero as the staircase partition grows. Secondly, for partitions whose Durfee size is $k$ where $k\geq3$, by semigroup property, we show that there exists a number $n_k$ such that if the tensor squares of the first $n_k$ staircase partitions contain all irreducible representations corresponding to partitions with Durfee size $k$, then all tensor squares contain partitions with Durfee size $k$. Specially, we show that $n_3=14$ and $n_4=28$. Furthermore, with the help of computer we show that the Saxl conjecture is true for all triple-hooks (i.e. partitions with Durfee size 3). Similar results for chopped square and caret shapes are also discussed.
Comment: We are grateful to the editors and reviewers whose suggestions improve this paper greatly. To appear in Disc. Math