./Ultimate.py --spec ../../sv-benchmarks/c/properties/unreach-call.prp --file ../../sv-benchmarks/c/hardware-verification-bv/btor2c-lazyMod.telephony.2.prop1-func-interl.c --full-output --architecture 64bit -------------------------------------------------------------------------------- Checking for ERROR reachability Using default analysis Version b5237d83 Calling Ultimate with: /usr/lib/jvm/java-11-openjdk-amd64/bin/java -Dosgi.configuration.area=/tmp/vcloud_worker_vcloud-master_on_vcloud-master/run_dir_a8edb296-7060-4937-9b3f-51f91541cacb/bin/ukojak-jW3SillKbg/data/config -Xmx15G -Xms4m -jar /tmp/vcloud_worker_vcloud-master_on_vcloud-master/run_dir_a8edb296-7060-4937-9b3f-51f91541cacb/bin/ukojak-jW3SillKbg/plugins/org.eclipse.equinox.launcher_1.5.800.v20200727-1323.jar -data @noDefault -ultimatedata /tmp/vcloud_worker_vcloud-master_on_vcloud-master/run_dir_a8edb296-7060-4937-9b3f-51f91541cacb/bin/ukojak-jW3SillKbg/data -tc /tmp/vcloud_worker_vcloud-master_on_vcloud-master/run_dir_a8edb296-7060-4937-9b3f-51f91541cacb/bin/ukojak-jW3SillKbg/config/KojakReach.xml -i ../../sv-benchmarks/c/hardware-verification-bv/btor2c-lazyMod.telephony.2.prop1-func-interl.c -s /tmp/vcloud_worker_vcloud-master_on_vcloud-master/run_dir_a8edb296-7060-4937-9b3f-51f91541cacb/bin/ukojak-jW3SillKbg/config/svcomp-Reach-64bit-Kojak_Default.epf --cacsl2boogietranslator.entry.function main --witnessprinter.witness.directory /tmp/vcloud_worker_vcloud-master_on_vcloud-master/run_dir_a8edb296-7060-4937-9b3f-51f91541cacb/bin/ukojak-jW3SillKbg --witnessprinter.witness.filename witness.graphml --witnessprinter.write.witness.besides.input.file false --witnessprinter.graph.data.specification CHECK( init(main()), LTL(G ! call(reach_error())) ) --witnessprinter.graph.data.producer Kojak --witnessprinter.graph.data.architecture 64bit --witnessprinter.graph.data.programhash e94f6dd671f1704573d790db68f6debf23755ffd14782b991a6c99403cf39b3b --- Real Ultimate output --- [0.001s][warning][os,container] Duplicate cpuset controllers detected. Picking /sys/fs/cgroup/cpuset, skipping /sys/fs/cgroup/cpuset. This is Ultimate 0.2.2-dev-b5237d8 [2022-11-21 22:17:23,549 INFO L177 SettingsManager]: Resetting all preferences to default values... [2022-11-21 22:17:23,552 INFO L181 SettingsManager]: Resetting UltimateCore preferences to default values [2022-11-21 22:17:23,592 INFO L184 SettingsManager]: Ultimate Commandline Interface provides no preferences, ignoring... [2022-11-21 22:17:23,595 INFO L181 SettingsManager]: Resetting Boogie Preprocessor preferences to default values [2022-11-21 22:17:23,597 INFO L181 SettingsManager]: Resetting Boogie Procedure Inliner preferences to default values [2022-11-21 22:17:23,599 INFO L181 SettingsManager]: Resetting Abstract Interpretation preferences to default values [2022-11-21 22:17:23,604 INFO L181 SettingsManager]: Resetting LassoRanker preferences to default values [2022-11-21 22:17:23,606 INFO L181 SettingsManager]: Resetting Reaching Definitions preferences to default values [2022-11-21 22:17:23,607 INFO L181 SettingsManager]: Resetting SyntaxChecker preferences to default values [2022-11-21 22:17:23,608 INFO L181 SettingsManager]: Resetting Sifa preferences to default values [2022-11-21 22:17:23,609 INFO L184 SettingsManager]: Büchi Program Product provides no preferences, ignoring... [2022-11-21 22:17:23,610 INFO L181 SettingsManager]: Resetting LTL2Aut preferences to default values [2022-11-21 22:17:23,611 INFO L181 SettingsManager]: Resetting PEA to Boogie preferences to default values [2022-11-21 22:17:23,612 INFO L181 SettingsManager]: Resetting BlockEncodingV2 preferences to default values [2022-11-21 22:17:23,615 INFO L181 SettingsManager]: Resetting ChcToBoogie preferences to default values [2022-11-21 22:17:23,617 INFO L181 SettingsManager]: Resetting AutomataScriptInterpreter preferences to default values [2022-11-21 22:17:23,621 INFO L181 SettingsManager]: Resetting BuchiAutomizer preferences to default values [2022-11-21 22:17:23,623 INFO L181 SettingsManager]: Resetting CACSL2BoogieTranslator preferences to default values [2022-11-21 22:17:23,642 INFO L181 SettingsManager]: Resetting CodeCheck preferences to default values [2022-11-21 22:17:23,644 INFO L181 SettingsManager]: Resetting InvariantSynthesis preferences to default values [2022-11-21 22:17:23,648 INFO L181 SettingsManager]: Resetting RCFGBuilder preferences to default values [2022-11-21 22:17:23,649 INFO L181 SettingsManager]: Resetting Referee preferences to default values [2022-11-21 22:17:23,650 INFO L181 SettingsManager]: Resetting TraceAbstraction preferences to default values [2022-11-21 22:17:23,653 INFO L184 SettingsManager]: TraceAbstractionConcurrent provides no preferences, ignoring... [2022-11-21 22:17:23,653 INFO L184 SettingsManager]: TraceAbstractionWithAFAs provides no preferences, ignoring... [2022-11-21 22:17:23,654 INFO L181 SettingsManager]: Resetting TreeAutomizer preferences to default values [2022-11-21 22:17:23,660 INFO L181 SettingsManager]: Resetting IcfgToChc preferences to default values [2022-11-21 22:17:23,665 INFO L181 SettingsManager]: Resetting IcfgTransformer preferences to default values [2022-11-21 22:17:23,666 INFO L184 SettingsManager]: ReqToTest provides no preferences, ignoring... [2022-11-21 22:17:23,667 INFO L181 SettingsManager]: Resetting Boogie Printer preferences to default values [2022-11-21 22:17:23,667 INFO L181 SettingsManager]: Resetting ChcSmtPrinter preferences to default values [2022-11-21 22:17:23,668 INFO L181 SettingsManager]: Resetting ReqPrinter preferences to default values [2022-11-21 22:17:23,669 INFO L181 SettingsManager]: Resetting Witness Printer preferences to default values [2022-11-21 22:17:23,671 INFO L184 SettingsManager]: Boogie PL CUP Parser provides no preferences, ignoring... [2022-11-21 22:17:23,672 INFO L181 SettingsManager]: Resetting CDTParser preferences to default values [2022-11-21 22:17:23,673 INFO L184 SettingsManager]: AutomataScriptParser provides no preferences, ignoring... [2022-11-21 22:17:23,673 INFO L184 SettingsManager]: ReqParser provides no preferences, ignoring... [2022-11-21 22:17:23,674 INFO L181 SettingsManager]: Resetting SmtParser preferences to default values [2022-11-21 22:17:23,675 INFO L181 SettingsManager]: Resetting Witness Parser preferences to default values [2022-11-21 22:17:23,676 INFO L188 SettingsManager]: Finished resetting all preferences to default values... [2022-11-21 22:17:23,677 INFO L101 SettingsManager]: Beginning loading settings from /tmp/vcloud_worker_vcloud-master_on_vcloud-master/run_dir_a8edb296-7060-4937-9b3f-51f91541cacb/bin/ukojak-jW3SillKbg/config/svcomp-Reach-64bit-Kojak_Default.epf [2022-11-21 22:17:23,718 INFO L113 SettingsManager]: Loading preferences was successful [2022-11-21 22:17:23,723 INFO L115 SettingsManager]: Preferences different from defaults after loading the file: [2022-11-21 22:17:23,724 INFO L136 SettingsManager]: Preferences of Boogie Procedure Inliner differ from their defaults: [2022-11-21 22:17:23,725 INFO L138 SettingsManager]: * Ignore calls to procedures called more than once=ALWAYS [2022-11-21 22:17:23,726 INFO L136 SettingsManager]: Preferences of BlockEncodingV2 differ from their defaults: [2022-11-21 22:17:23,727 INFO L138 SettingsManager]: * Create parallel compositions if possible=false [2022-11-21 22:17:23,728 INFO L136 SettingsManager]: Preferences of CACSL2BoogieTranslator differ from their defaults: [2022-11-21 22:17:23,728 INFO L138 SettingsManager]: * Overapproximate operations on floating types=true [2022-11-21 22:17:23,728 INFO L138 SettingsManager]: * Check division by zero=IGNORE [2022-11-21 22:17:23,728 INFO L138 SettingsManager]: * Pointer to allocated memory at dereference=IGNORE [2022-11-21 22:17:23,730 INFO L138 SettingsManager]: * If two pointers are subtracted or compared they have the same base address=IGNORE [2022-11-21 22:17:23,730 INFO L138 SettingsManager]: * Check array bounds for arrays that are off heap=IGNORE [2022-11-21 22:17:23,730 INFO L138 SettingsManager]: * Check if freed pointer was valid=false [2022-11-21 22:17:23,730 INFO L138 SettingsManager]: * Use constant arrays=true [2022-11-21 22:17:23,731 INFO L138 SettingsManager]: * Pointer base address is valid at dereference=IGNORE [2022-11-21 22:17:23,731 INFO L136 SettingsManager]: Preferences of CodeCheck differ from their defaults: [2022-11-21 22:17:23,731 INFO L138 SettingsManager]: * Timeout in seconds=1000000 [2022-11-21 22:17:23,731 INFO L136 SettingsManager]: Preferences of RCFGBuilder differ from their defaults: [2022-11-21 22:17:23,732 INFO L138 SettingsManager]: * Command for external solver=z3 SMTLIB2_COMPLIANT=true -memory:2024 -smt2 -in -t:10000 [2022-11-21 22:17:23,732 INFO L136 SettingsManager]: Preferences of TraceAbstraction differ from their defaults: [2022-11-21 22:17:23,732 INFO L138 SettingsManager]: * Compute Interpolants along a Counterexample=FPandBP [2022-11-21 22:17:23,732 INFO L138 SettingsManager]: * Positions where we compute the Hoare Annotation=LoopsAndPotentialCycles [2022-11-21 22:17:23,732 INFO L138 SettingsManager]: * Trace refinement strategy=PENGUIN [2022-11-21 22:17:23,733 INFO L138 SettingsManager]: * Command for external solver=z3 SMTLIB2_COMPLIANT=true -memory:2024 -smt2 -in [2022-11-21 22:17:23,733 INFO L138 SettingsManager]: * Compute Hoare Annotation of negated interpolant automaton, abstraction and CFG=true [2022-11-21 22:17:23,733 INFO L138 SettingsManager]: * SMT solver=External_ModelsAndUnsatCoreMode WARNING: An illegal reflective access operation has occurred WARNING: Illegal reflective access by com.sun.xml.bind.v2.runtime.reflect.opt.Injector$1 (file:/tmp/vcloud_worker_vcloud-master_on_vcloud-master/run_dir_a8edb296-7060-4937-9b3f-51f91541cacb/bin/ukojak-jW3SillKbg/plugins/com.sun.xml.bind_2.2.0.v201505121915.jar) to method java.lang.ClassLoader.defineClass(java.lang.String,byte[],int,int) WARNING: Please consider reporting this to the maintainers of com.sun.xml.bind.v2.runtime.reflect.opt.Injector$1 WARNING: Use --illegal-access=warn to enable warnings of further illegal reflective access operations WARNING: All illegal access operations will be denied in a future release Applying setting for plugin de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator: Entry function -> main Applying setting for plugin de.uni_freiburg.informatik.ultimate.witnessprinter: Witness directory -> /tmp/vcloud_worker_vcloud-master_on_vcloud-master/run_dir_a8edb296-7060-4937-9b3f-51f91541cacb/bin/ukojak-jW3SillKbg Applying setting for plugin de.uni_freiburg.informatik.ultimate.witnessprinter: Witness filename -> witness.graphml Applying setting for plugin de.uni_freiburg.informatik.ultimate.witnessprinter: Write witness besides input file -> false Applying setting for plugin de.uni_freiburg.informatik.ultimate.witnessprinter: Graph data specification -> CHECK( init(main()), LTL(G ! call(reach_error())) ) Applying setting for plugin de.uni_freiburg.informatik.ultimate.witnessprinter: Graph data producer -> Kojak Applying setting for plugin de.uni_freiburg.informatik.ultimate.witnessprinter: Graph data architecture -> 64bit Applying setting for plugin de.uni_freiburg.informatik.ultimate.witnessprinter: Graph data programhash -> e94f6dd671f1704573d790db68f6debf23755ffd14782b991a6c99403cf39b3b [2022-11-21 22:17:24,041 INFO L75 nceAwareModelManager]: Repository-Root is: /tmp [2022-11-21 22:17:24,073 INFO L261 ainManager$Toolchain]: [Toolchain 1]: Applicable parser(s) successfully (re)initialized [2022-11-21 22:17:24,076 INFO L217 ainManager$Toolchain]: [Toolchain 1]: Toolchain selected. [2022-11-21 22:17:24,077 INFO L271 PluginConnector]: Initializing CDTParser... [2022-11-21 22:17:24,077 INFO L275 PluginConnector]: CDTParser initialized [2022-11-21 22:17:24,079 INFO L432 ainManager$Toolchain]: [Toolchain 1]: Parsing single file: /tmp/vcloud_worker_vcloud-master_on_vcloud-master/run_dir_a8edb296-7060-4937-9b3f-51f91541cacb/bin/ukojak-jW3SillKbg/../../sv-benchmarks/c/hardware-verification-bv/btor2c-lazyMod.telephony.2.prop1-func-interl.c [2022-11-21 22:17:27,183 INFO L500 CDTParser]: Created temporary CDT project at NULL [2022-11-21 22:17:27,673 INFO L351 CDTParser]: Found 1 translation units. [2022-11-21 22:17:27,674 INFO L172 CDTParser]: Scanning /tmp/vcloud_worker_vcloud-master_on_vcloud-master/run_dir_a8edb296-7060-4937-9b3f-51f91541cacb/sv-benchmarks/c/hardware-verification-bv/btor2c-lazyMod.telephony.2.prop1-func-interl.c [2022-11-21 22:17:27,697 INFO L394 CDTParser]: About to delete temporary CDT project at /tmp/vcloud_worker_vcloud-master_on_vcloud-master/run_dir_a8edb296-7060-4937-9b3f-51f91541cacb/bin/ukojak-jW3SillKbg/data/df57a4464/5bcb5b048f1f4325a65ebff8ae520da0/FLAGba3263d48 [2022-11-21 22:17:27,716 INFO L402 CDTParser]: Successfully deleted /tmp/vcloud_worker_vcloud-master_on_vcloud-master/run_dir_a8edb296-7060-4937-9b3f-51f91541cacb/bin/ukojak-jW3SillKbg/data/df57a4464/5bcb5b048f1f4325a65ebff8ae520da0 [2022-11-21 22:17:27,721 INFO L299 ainManager$Toolchain]: ####################### [Toolchain 1] ####################### [2022-11-21 22:17:27,723 INFO L131 ToolchainWalker]: Walking toolchain with 6 elements. [2022-11-21 22:17:27,724 INFO L113 PluginConnector]: ------------------------CACSL2BoogieTranslator---------------------------- [2022-11-21 22:17:27,725 INFO L271 PluginConnector]: Initializing CACSL2BoogieTranslator... [2022-11-21 22:17:27,728 INFO L275 PluginConnector]: CACSL2BoogieTranslator initialized [2022-11-21 22:17:27,729 INFO L185 PluginConnector]: Executing the observer ACSLObjectContainerObserver from plugin CACSL2BoogieTranslator for "CDTParser AST 21.11 10:17:27" (1/1) ... [2022-11-21 22:17:27,730 INFO L205 PluginConnector]: Invalid model from CACSL2BoogieTranslator for observer de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator.ACSLObjectContainerObserver@c06d28a and model type de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 21.11 10:17:27, skipping insertion in model container [2022-11-21 22:17:27,730 INFO L185 PluginConnector]: Executing the observer CACSL2BoogieTranslatorObserver from plugin CACSL2BoogieTranslator for "CDTParser AST 21.11 10:17:27" (1/1) ... [2022-11-21 22:17:27,738 INFO L145 MainTranslator]: Starting translation in SV-COMP mode [2022-11-21 22:17:27,859 INFO L178 MainTranslator]: Built tables and reachable declarations [2022-11-21 22:17:28,150 WARN L237 ndardFunctionHandler]: Function reach_error is already implemented but we override the implementation for the call at /tmp/vcloud_worker_vcloud-master_on_vcloud-master/run_dir_a8edb296-7060-4937-9b3f-51f91541cacb/sv-benchmarks/c/hardware-verification-bv/btor2c-lazyMod.telephony.2.prop1-func-interl.c[1014,1027] [2022-11-21 22:17:28,728 INFO L210 PostProcessor]: Analyzing one entry point: main [2022-11-21 22:17:28,734 INFO L203 MainTranslator]: Completed pre-run [2022-11-21 22:17:28,746 WARN L237 ndardFunctionHandler]: Function reach_error is already implemented but we override the implementation for the call at /tmp/vcloud_worker_vcloud-master_on_vcloud-master/run_dir_a8edb296-7060-4937-9b3f-51f91541cacb/sv-benchmarks/c/hardware-verification-bv/btor2c-lazyMod.telephony.2.prop1-func-interl.c[1014,1027] [2022-11-21 22:17:29,119 INFO L210 PostProcessor]: Analyzing one entry point: main [2022-11-21 22:17:29,132 INFO L208 MainTranslator]: Completed translation [2022-11-21 22:17:29,133 INFO L202 PluginConnector]: Adding new model de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 21.11 10:17:29 WrapperNode [2022-11-21 22:17:29,133 INFO L132 PluginConnector]: ------------------------ END CACSL2BoogieTranslator---------------------------- [2022-11-21 22:17:29,135 INFO L113 PluginConnector]: ------------------------Boogie Procedure Inliner---------------------------- [2022-11-21 22:17:29,135 INFO L271 PluginConnector]: Initializing Boogie Procedure Inliner... [2022-11-21 22:17:29,135 INFO L275 PluginConnector]: Boogie Procedure Inliner initialized [2022-11-21 22:17:29,144 INFO L185 PluginConnector]: Executing the observer TypeChecker from plugin Boogie Procedure Inliner for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 21.11 10:17:29" (1/1) ... [2022-11-21 22:17:29,232 INFO L185 PluginConnector]: Executing the observer Inliner from plugin Boogie Procedure Inliner for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 21.11 10:17:29" (1/1) ... [2022-11-21 22:17:29,584 INFO L138 Inliner]: procedures = 11, calls = 3, calls flagged for inlining = 3, calls inlined = 3, statements flattened = 4507 [2022-11-21 22:17:29,585 INFO L132 PluginConnector]: ------------------------ END Boogie Procedure Inliner---------------------------- [2022-11-21 22:17:29,586 INFO L113 PluginConnector]: ------------------------Boogie Preprocessor---------------------------- [2022-11-21 22:17:29,587 INFO L271 PluginConnector]: Initializing Boogie Preprocessor... [2022-11-21 22:17:29,587 INFO L275 PluginConnector]: Boogie Preprocessor initialized [2022-11-21 22:17:29,596 INFO L185 PluginConnector]: Executing the observer EnsureBoogieModelObserver from plugin Boogie Preprocessor for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 21.11 10:17:29" (1/1) ... [2022-11-21 22:17:29,597 INFO L185 PluginConnector]: Executing the observer TypeChecker from plugin Boogie Preprocessor for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 21.11 10:17:29" (1/1) ... [2022-11-21 22:17:29,666 INFO L185 PluginConnector]: Executing the observer ConstExpander from plugin Boogie Preprocessor for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 21.11 10:17:29" (1/1) ... [2022-11-21 22:17:29,666 INFO L185 PluginConnector]: Executing the observer StructExpander from plugin Boogie Preprocessor for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 21.11 10:17:29" (1/1) ... [2022-11-21 22:17:29,766 INFO L185 PluginConnector]: Executing the observer UnstructureCode from plugin Boogie Preprocessor for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 21.11 10:17:29" (1/1) ... [2022-11-21 22:17:29,775 INFO L185 PluginConnector]: Executing the observer FunctionInliner from plugin Boogie Preprocessor for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 21.11 10:17:29" (1/1) ... [2022-11-21 22:17:29,795 INFO L185 PluginConnector]: Executing the observer LTLStepAnnotator from plugin Boogie Preprocessor for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 21.11 10:17:29" (1/1) ... [2022-11-21 22:17:29,809 INFO L185 PluginConnector]: Executing the observer BoogieSymbolTableConstructor from plugin Boogie Preprocessor for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 21.11 10:17:29" (1/1) ... [2022-11-21 22:17:29,844 INFO L132 PluginConnector]: ------------------------ END Boogie Preprocessor---------------------------- [2022-11-21 22:17:29,845 INFO L113 PluginConnector]: ------------------------RCFGBuilder---------------------------- [2022-11-21 22:17:29,845 INFO L271 PluginConnector]: Initializing RCFGBuilder... [2022-11-21 22:17:29,845 INFO L275 PluginConnector]: RCFGBuilder initialized [2022-11-21 22:17:29,846 INFO L185 PluginConnector]: Executing the observer RCFGBuilderObserver from plugin RCFGBuilder for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 21.11 10:17:29" (1/1) ... [2022-11-21 22:17:29,853 INFO L173 SolverBuilder]: Constructing external solver with command: z3 SMTLIB2_COMPLIANT=true -memory:2024 -smt2 -in -t:10000 [2022-11-21 22:17:29,864 INFO L189 MonitoredProcess]: No working directory specified, using /tmp/vcloud_worker_vcloud-master_on_vcloud-master/run_dir_a8edb296-7060-4937-9b3f-51f91541cacb/bin/ukojak-jW3SillKbg/z3 [2022-11-21 22:17:29,884 INFO L229 MonitoredProcess]: Starting monitored process 1 with /tmp/vcloud_worker_vcloud-master_on_vcloud-master/run_dir_a8edb296-7060-4937-9b3f-51f91541cacb/bin/ukojak-jW3SillKbg/z3 SMTLIB2_COMPLIANT=true -memory:2024 -smt2 -in -t:10000 (exit command is (exit), workingDir is null) [2022-11-21 22:17:29,902 INFO L327 MonitoredProcess]: [MP /tmp/vcloud_worker_vcloud-master_on_vcloud-master/run_dir_a8edb296-7060-4937-9b3f-51f91541cacb/bin/ukojak-jW3SillKbg/z3 SMTLIB2_COMPLIANT=true -memory:2024 -smt2 -in -t:10000 (1)] Waiting until timeout for monitored process [2022-11-21 22:17:29,942 INFO L130 BoogieDeclarations]: Found specification of procedure ULTIMATE.start [2022-11-21 22:17:29,943 INFO L138 BoogieDeclarations]: Found implementation of procedure ULTIMATE.start [2022-11-21 22:17:30,785 INFO L235 CfgBuilder]: Building ICFG [2022-11-21 22:17:30,788 INFO L261 CfgBuilder]: Building CFG for each procedure with an implementation