Proposal for Notation at Tricritical Points

A notation for critical exponents at a tricritical point is proposed on the basis that the line of critical points observed experimentally in metamagnets, N${\mathrm{H}}_{4}$Cl, or ${\mathrm{He}}^{3}$-${\mathrm{He}}^{4}$ mixtures defines a special direction in the space of thermodynamic parameters. Scaling at a tricritical point implies certain relations among the exponents which are summarized in a table.