Свързани concepts
Isolatedpoint:ThepointinVthatisnotassociatedwithanyedgeinEiscalledtheisolatedpointofD.
Simplegraph:Agraphwithoutparalleledgesiscalledasimplegraph.
Completegraph:BetweenanytwoverticesUanduinthegraph,thereareexactlytwodirectededges(u,v),and(v,u),thenCallthedirectedgraphDacompletegraph.
Basicgraph:RemoveeachedgeofthedirectedgraphDtogetacorrespondingundirectedgraphG,whichiscalledthebasicgraphofD.CalldTheDirectionAlgraphofg.
Stronglyconnectedgraph:GivenadirectedgraphG=(VE),andgivenanytwonodesuandvinthegraphG,ifthenodeuItismutuallyreachablewithnodev,thatis,thereisatleastonepaththatcanstartfromnodeuandendatnodev,andthereisatleastonepaththatcanstartfromnodevandendatnodeu,thenitissaidthatthereshouldbeThedigraphGisastronglyconnectedgraph.
Weaklyconnectedgraph:Ifatleastonepairofnodesdoesnotsatisfyone-wayconnectivity,butafterremovingtheedgedirection,itisaconnectedgraphfromthepointofviewofanundirectedgraph,thenDiscalledItisaweaklyconnectedgraph.
One-wayconnectedgraph:Ifeachpairofnodesisconnectedinatleastonedirection,thenDiscalledaone-wayconnectedgraph.
Stronglyconnectedcomponent:TheextremelystronglyconnectedsubgraphofthedirectedgraphGiscalledthestronglyconnectedcomponentofthedirectedgraph.
Directedpath:Thereisalwayssuchanindependentset5inacyclicdirectedgraphD,sothatanypointiny-Js",thereexistsH∈S,fromMto"Thereisadirectedpathwithalengthnotexceeding2.
Матрица за съседство
С изключение на forsolated vertices, anyvertexisassociated withatlestoneedge.Следователно, anydirectedgraph, независимо от оформяните вещества, canbeComplelydescribedByitsEdgesetet.Например, ако краищата на смея, както следва:
(1,1), (1,2), (1,3), (1,4), (2,2), (2,3), (2,4), (3,3), (3, 4), (4,4),
NoteTheTheListEdgesofDAccorDingTotheDictionAryArySexe, но Bustheriisnota, b, c,..., но-1,2,3....
Според Totothisidea, WecanuseamatrixtocompletydescribeanyDirectedgraph.Thisisthedirectedgraphadjacencymatrix.
Решаване
FordEshortestPathProbleMofAdirectedGraph, theCalculationStepsarethesameassolvingtheshortestpathproblemofanundirectedgraph.ThemaindifferenceishattheshortestpathproblemofanundirectedgraphuseSasingLeLabelingMethod.Thesingle-labelingmethodistoassignaright-of-waylabeltoeachpoint и andforthedirectedshortestpathproblem, thedouble-labelingmethodisususedusedusedusedusedusedused.Thedoublelabelingmethodistoassigntwolabelstoeachpoint: thepathandTherofway.
Достъпност
ForanUndirectedGraph, ifitisconnected, thentHereMustBeapathbetweenOnyTwoverticesOfit.Следователно, чрез този „обхват“ от OoneVertextoanotherexex.Ifthevertex "canreachu, thenitcanalsoraceachu", thatis, vanduaremutatualreaceable.
Fordirectedgraphs, thesitucationisdifferent, becausethereisapathfromutov, което се налага по.
Предполагаемииран график, andu, v∈D, ifTheReisapathFromverTexutOverTexv, thenitissAidThatVertExvToverTexuiSreace -Quableable.
TheConceptOfДостъпностhasnothingtodowithThenumberandLengthOfTheVariousPathsfromutov.В допълнение, forsesakeofCompletiness, itiSstipulatedthatanyvertextoitself е повдигащ.
AccessibilityIsabinaryRelationshipbetweEntericeSofAdirectiledGraph.Според TotheDefinition, ItisreflexiveandTransive.Като цяло говорещи, достъпни енезиметричнинорантисиметрични.