:: deftheorem Def19 defines min-cost GLIB_004:def 19 :
for G1 being _finite connected real-weighted WGraph
for G2 being spanning Tree-like WSubgraph of G1 holds
( G2 is min-cost iff for G3 being spanning Tree-like WSubgraph of G1 holds G2 .cost() <= G3 .cost() );