26-0126axx26bxx26dxx03exx calculus compact(locallycompact)metricspaces completemetricspaces functionalanalysis functionsofrealvariables functionsofseveralvariables generaltopology inequalities instructionalexposition(textbooks mathematicalanalysis mathematicallogicandfoundations metricspaces metrizability one-variablecalculus realfunctions settheory spaceswithricherstructures tutorialpapers