3 problems

The ABK Conjecture on countable unions of bqos
A well-quasi-order (wqo) is a quasi-order with no infinite descending sequence and no infinite antichain; a better-quasi-order (bqo) is a wqo satisfying the stronger Ramsey-theoret…
openFrom papersbetter-quasi-orders order-theory well-quasi-orders
0 responses
8
Better-quasi-order conjecture for continuous rational-valued functions
Let $[\omega]^2_+$ denote the relevant domain of ordered pairs of natural numbers, let $C([\omega]^2_+,\mathbb{Q})$ be the space of continuous functions from this domain to…
openFrom papersbetter-quasi-orders descriptive-set-theory embeddability
0 responses
4
The countable-union conjecture for well-quasi-orders
Countable-union conjecture. Every well-quasi-ordered poset is a countable union of better quasi-orders.
openFrom papersbetter-quasi-orders order-theory well-quasi-orders
0 responses
5

The ABK Conjecture on countable unions of bqos