<?xml version="1.0" encoding="UTF-8"?>
<!-- Generated by Fujitsu Interstage XWand B0254 -->
<!-- Generated by Broadridge Financial Solutions Inc -->
<link:linkbase xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd" xmlns:tsr="http://tsr/20260531" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xmlns:xbrli="http://www.xbrl.org/2003/instance" xmlns:xlink="http://www.w3.org/1999/xlink">
  <link:roleRef roleURI="http://xbrl.sec.gov/oef/role/Defaults" xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#Defaults"/>
  <link:roleRef roleURI="http://xbrl.sec.gov/oef/role/ShareholderReport" xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#ShareholderReport"/>
  <link:roleRef roleURI="http://xbrl.sec.gov/oef/role/ClassOnly" xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#ClassOnly"/>
  <link:roleRef roleURI="http://xbrl.sec.gov/oef/role/IndustrySectorOnly" xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#IndustrySectorOnly"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension"/>
  <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/oef/role/ClassOnly">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#oef_ShareClassDomain" xlink:label="ShareClassDomain"/>
    <link:loc xlink:type="locator" xlink:href="tsr-20260531.xsd#tsr_C000046414Member" xlink:label="C000046414Member"/>
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000046414Member" order="1.0"/>
    <link:loc xlink:type="locator" xlink:href="tsr-20260531.xsd#tsr_C000046415Member" xlink:label="C000046415Member"/>
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000046415Member" order="2.0"/>
    <link:loc xlink:type="locator" xlink:href="tsr-20260531.xsd#tsr_C000046416Member" xlink:label="C000046416Member"/>
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000046416Member" order="3.0"/>
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/oef/role/IndustrySectorOnly">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#oef_IndustrySectorDomain" xlink:label="IndustrySectorDomain"/>
    <link:loc xlink:type="locator" xlink:href="tsr-20260531.xsd#tsr_bench202407192617_7632Member" xlink:label="bench202407192617_7632Member"/>
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IndustrySectorDomain" xlink:to="bench202407192617_7632Member" order="4.0"/>
    <link:loc xlink:type="locator" xlink:href="tsr-20260531.xsd#tsr_bench202409033971_7632Member" xlink:label="bench202409033971_7632Member"/>
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IndustrySectorDomain" xlink:to="bench202409033971_7632Member" order="5.0"/>
    <link:loc xlink:type="locator" xlink:href="tsr-20260531.xsd#tsr_bench202407192615_7632Member" xlink:label="bench202407192615_7632Member"/>
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IndustrySectorDomain" xlink:to="bench202407192615_7632Member" order="6.0"/>
    <link:loc xlink:type="locator" xlink:href="tsr-20260531.xsd#tsr_bench202407192620_7632Member" xlink:label="bench202407192620_7632Member"/>
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IndustrySectorDomain" xlink:to="bench202407192620_7632Member" order="7.0"/>
    <link:loc xlink:type="locator" xlink:href="tsr-20260531.xsd#tsr_bench202407192625_7632Member" xlink:label="bench202407192625_7632Member"/>
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IndustrySectorDomain" xlink:to="bench202407192625_7632Member" order="8.0"/>
    <link:loc xlink:type="locator" xlink:href="tsr-20260531.xsd#tsr_bench202409033970_7632Member" xlink:label="bench202409033970_7632Member"/>
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IndustrySectorDomain" xlink:to="bench202409033970_7632Member" order="9.0"/>
    <link:loc xlink:type="locator" xlink:href="tsr-20260531.xsd#tsr_bench202407192623_7632Member" xlink:label="bench202407192623_7632Member"/>
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IndustrySectorDomain" xlink:to="bench202407192623_7632Member" order="10.0"/>
    <link:loc xlink:type="locator" xlink:href="tsr-20260531.xsd#tsr_bench202407222637_7632Member" xlink:label="bench202407222637_7632Member"/>
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IndustrySectorDomain" xlink:to="bench202407222637_7632Member" order="11.0"/>
    <link:loc xlink:type="locator" xlink:href="tsr-20260531.xsd#tsr_bench202407192626_7632Member" xlink:label="bench202407192626_7632Member"/>
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IndustrySectorDomain" xlink:to="bench202407192626_7632Member" order="12.0"/>
    <link:loc xlink:type="locator" xlink:href="tsr-20260531.xsd#tsr_bench202407192619_7632Member" xlink:label="bench202407192619_7632Member"/>
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IndustrySectorDomain" xlink:to="bench202407192619_7632Member" order="13.0"/>
    <link:loc xlink:type="locator" xlink:href="tsr-20260531.xsd#tsr_bench202407192627_7632Member" xlink:label="bench202407192627_7632Member"/>
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IndustrySectorDomain" xlink:to="bench202407192627_7632Member" order="14.0"/>
    <link:loc xlink:type="locator" xlink:href="tsr-20260531.xsd#tsr_bench202407192622_7632Member" xlink:label="bench202407192622_7632Member"/>
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IndustrySectorDomain" xlink:to="bench202407192622_7632Member" order="15.0"/>
    <link:loc xlink:type="locator" xlink:href="tsr-20260531.xsd#tsr_bench202407192618_7632Member" xlink:label="bench202407192618_7632Member"/>
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IndustrySectorDomain" xlink:to="bench202407192618_7632Member" order="16.0"/>
    <link:loc xlink:type="locator" xlink:href="tsr-20260531.xsd#tsr_bench202407222646_7632Member" xlink:label="bench202407222646_7632Member"/>
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IndustrySectorDomain" xlink:to="bench202407222646_7632Member" order="17.0"/>
    <link:loc xlink:type="locator" xlink:href="tsr-20260531.xsd#tsr_bench202407192617_7633Member" xlink:label="bench202407192617_7633Member"/>
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IndustrySectorDomain" xlink:to="bench202407192617_7633Member" order="4.0"/>
    <link:loc xlink:type="locator" xlink:href="tsr-20260531.xsd#tsr_bench202409033971_7633Member" xlink:label="bench202409033971_7633Member"/>
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IndustrySectorDomain" xlink:to="bench202409033971_7633Member" order="5.0"/>
    <link:loc xlink:type="locator" xlink:href="tsr-20260531.xsd#tsr_bench202407192615_7633Member" xlink:label="bench202407192615_7633Member"/>
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IndustrySectorDomain" xlink:to="bench202407192615_7633Member" order="6.0"/>
    <link:loc xlink:type="locator" xlink:href="tsr-20260531.xsd#tsr_bench202407192620_7633Member" xlink:label="bench202407192620_7633Member"/>
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IndustrySectorDomain" xlink:to="bench202407192620_7633Member" order="7.0"/>
    <link:loc xlink:type="locator" xlink:href="tsr-20260531.xsd#tsr_bench202407192625_7633Member" xlink:label="bench202407192625_7633Member"/>
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IndustrySectorDomain" xlink:to="bench202407192625_7633Member" order="8.0"/>
    <link:loc xlink:type="locator" xlink:href="tsr-20260531.xsd#tsr_bench202409033970_7633Member" xlink:label="bench202409033970_7633Member"/>
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IndustrySectorDomain" xlink:to="bench202409033970_7633Member" order="9.0"/>
    <link:loc xlink:type="locator" xlink:href="tsr-20260531.xsd#tsr_bench202407192623_7633Member" xlink:label="bench202407192623_7633Member"/>
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IndustrySectorDomain" xlink:to="bench202407192623_7633Member" order="10.0"/>
    <link:loc xlink:type="locator" xlink:href="tsr-20260531.xsd#tsr_bench202407222637_7633Member" xlink:label="bench202407222637_7633Member"/>
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IndustrySectorDomain" xlink:to="bench202407222637_7633Member" order="11.0"/>
    <link:loc xlink:type="locator" xlink:href="tsr-20260531.xsd#tsr_bench202407192626_7633Member" xlink:label="bench202407192626_7633Member"/>
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IndustrySectorDomain" xlink:to="bench202407192626_7633Member" order="12.0"/>
    <link:loc xlink:type="locator" xlink:href="tsr-20260531.xsd#tsr_bench202407192619_7633Member" xlink:label="bench202407192619_7633Member"/>
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IndustrySectorDomain" xlink:to="bench202407192619_7633Member" order="13.0"/>
    <link:loc xlink:type="locator" xlink:href="tsr-20260531.xsd#tsr_bench202407192627_7633Member" xlink:label="bench202407192627_7633Member"/>
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IndustrySectorDomain" xlink:to="bench202407192627_7633Member" order="14.0"/>
    <link:loc xlink:type="locator" xlink:href="tsr-20260531.xsd#tsr_bench202407192622_7633Member" xlink:label="bench202407192622_7633Member"/>
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IndustrySectorDomain" xlink:to="bench202407192622_7633Member" order="15.0"/>
    <link:loc xlink:type="locator" xlink:href="tsr-20260531.xsd#tsr_bench202407192618_7633Member" xlink:label="bench202407192618_7633Member"/>
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IndustrySectorDomain" xlink:to="bench202407192618_7633Member" order="16.0"/>
    <link:loc xlink:type="locator" xlink:href="tsr-20260531.xsd#tsr_bench202407222646_7633Member" xlink:label="bench202407222646_7633Member"/>
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IndustrySectorDomain" xlink:to="bench202407222646_7633Member" order="17.0"/>
    <link:loc xlink:type="locator" xlink:href="tsr-20260531.xsd#tsr_bench202407192617_7634Member" xlink:label="bench202407192617_7634Member"/>
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IndustrySectorDomain" xlink:to="bench202407192617_7634Member" order="4.0"/>
    <link:loc xlink:type="locator" xlink:href="tsr-20260531.xsd#tsr_bench202409033971_7634Member" xlink:label="bench202409033971_7634Member"/>
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IndustrySectorDomain" xlink:to="bench202409033971_7634Member" order="5.0"/>
    <link:loc xlink:type="locator" xlink:href="tsr-20260531.xsd#tsr_bench202407192615_7634Member" xlink:label="bench202407192615_7634Member"/>
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IndustrySectorDomain" xlink:to="bench202407192615_7634Member" order="6.0"/>
    <link:loc xlink:type="locator" xlink:href="tsr-20260531.xsd#tsr_bench202407192620_7634Member" xlink:label="bench202407192620_7634Member"/>
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IndustrySectorDomain" xlink:to="bench202407192620_7634Member" order="7.0"/>
    <link:loc xlink:type="locator" xlink:href="tsr-20260531.xsd#tsr_bench202407192625_7634Member" xlink:label="bench202407192625_7634Member"/>
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IndustrySectorDomain" xlink:to="bench202407192625_7634Member" order="8.0"/>
    <link:loc xlink:type="locator" xlink:href="tsr-20260531.xsd#tsr_bench202409033970_7634Member" xlink:label="bench202409033970_7634Member"/>
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IndustrySectorDomain" xlink:to="bench202409033970_7634Member" order="9.0"/>
    <link:loc xlink:type="locator" xlink:href="tsr-20260531.xsd#tsr_bench202407192623_7634Member" xlink:label="bench202407192623_7634Member"/>
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IndustrySectorDomain" xlink:to="bench202407192623_7634Member" order="10.0"/>
    <link:loc xlink:type="locator" xlink:href="tsr-20260531.xsd#tsr_bench202407222637_7634Member" xlink:label="bench202407222637_7634Member"/>
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IndustrySectorDomain" xlink:to="bench202407222637_7634Member" order="11.0"/>
    <link:loc xlink:type="locator" xlink:href="tsr-20260531.xsd#tsr_bench202407192626_7634Member" xlink:label="bench202407192626_7634Member"/>
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IndustrySectorDomain" xlink:to="bench202407192626_7634Member" order="12.0"/>
    <link:loc xlink:type="locator" xlink:href="tsr-20260531.xsd#tsr_bench202407192619_7634Member" xlink:label="bench202407192619_7634Member"/>
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IndustrySectorDomain" xlink:to="bench202407192619_7634Member" order="13.0"/>
    <link:loc xlink:type="locator" xlink:href="tsr-20260531.xsd#tsr_bench202407192627_7634Member" xlink:label="bench202407192627_7634Member"/>
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IndustrySectorDomain" xlink:to="bench202407192627_7634Member" order="14.0"/>
    <link:loc xlink:type="locator" xlink:href="tsr-20260531.xsd#tsr_bench202407192622_7634Member" xlink:label="bench202407192622_7634Member"/>
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IndustrySectorDomain" xlink:to="bench202407192622_7634Member" order="15.0"/>
    <link:loc xlink:type="locator" xlink:href="tsr-20260531.xsd#tsr_bench202407192618_7634Member" xlink:label="bench202407192618_7634Member"/>
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IndustrySectorDomain" xlink:to="bench202407192618_7634Member" order="16.0"/>
    <link:loc xlink:type="locator" xlink:href="tsr-20260531.xsd#tsr_bench202407222646_7634Member" xlink:label="bench202407222646_7634Member"/>
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IndustrySectorDomain" xlink:to="bench202407222646_7634Member" order="17.0"/>
  </link:definitionLink>
</link:linkbase>
