House Speaker Dade Phelan and Lt. Gov. Dan Patrick, the two top Republicans in the Texas Legislature, have dug in their heels on how to reduce property owners’ tax burden — with dueling proposals on how to get it done and a path to a potential compromise unclear. Patrick wants to raise the state’s homestead exemption — the dollar amount of a home’s value that can’t be taxed — on school district property taxes, with an additional boost for seniors.