fact: Record valid_contract : Prop := ValidContract { valid_contract_is_off_ring : [disjoint r & insertE cc]; valid_contract_is_sparse : sparse (insertE cc); valid_contract_size : pred4 1 2 3 4 (size cc); valid_contract_triad : size cc = 4 -> ~~ [disjoint kernel r & triad (insertE cc)] }.
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(fintype path fingraph) fourcolor(hypermap walkup geometry color chromogram)