<?xml version="1.0" encoding="UTF-8"?>
<sbml xmlns="http://www.sbml.org/sbml/level2/version4" level="2" version="4">
    <model id="BoundaryCondExampleModel">
        <listOfUnitDefinitions>
            <unitDefinition id="mole_per_litre_per_second">
                <listOfUnits>
                    <unit kind="mole" />
                    <unit kind="litre" exponent="-1"/>
                    <unit kind="second" exponent="-1"/>
                </listOfUnits>
            </unitDefinition>
            <unitDefinition id="litre_sq_per_mole_sq_per_second">
                <listOfUnits>
                    <unit kind="mole" exponent="-2"/>
                    <unit kind="litre" exponent="2"/>
                    <unit kind="second" exponent="-1"/>
                </listOfUnits>
            </unitDefinition>
        </listOfUnitDefinitions>
        <listOfCompartments>
            <compartment id="compartmentOne" size="1"/>
        </listOfCompartments>
        <listOfSpecies>
            <species id="S1" initialConcentration="0" compartment="compartmentOne" 
                             boundaryCondition="true"/>
            <species id="S2" initialConcentration="1" compartment="compartmentOne" 
                             boundaryCondition="true" constant="true"/>
            <species id="S3" initialConcentration="3" compartment="compartmentOne" 
                             constant="true"/>
            <species id="S4" initialConcentration="0" compartment="compartmentOne"/>
        </listOfSpecies>
        <listOfParameters>
            <parameter id="k1" value="0.5" units="litre_sq_per_mole_sq_per_second"/>
            <parameter id="k2" value="0.1" units="mole_per_litre_per_second"/>
        </listOfParameters>
        <listOfRules>
            <rateRule variable="S1">
                <math xmlns="http://www.w3.org/1998/Math/MathML">
                    <ci> k2 </ci>
                </math>
            </rateRule>
        </listOfRules>
        <listOfReactions>
            <reaction id="reaction_1" reversible="false">
                <listOfReactants>
                    <speciesReference species="S1"/>
                    <speciesReference species="S2"/>
                </listOfReactants>
                <listOfProducts>
                    <speciesReference species="S4"/>
                </listOfProducts>
                <listOfModifiers>
                    <modifierSpeciesReference species="S3"/>
                </listOfModifiers>
                <kineticLaw>
                    <math xmlns="http://www.w3.org/1998/Math/MathML">
                        <apply>
                            <times/>
                            <ci> k1 </ci>
                            <ci> S1 </ci>
                            <ci> S2 </ci>
                            <ci> S3 </ci>
                            <ci> compartmentOne </ci>
                        </apply>
                    </math>
                </kineticLaw>
            </reaction>
        </listOfReactions>
    </model>
</sbml>
