A natural generalization of Balanced Tableaux

We introduce the notion of "type" of a tableau, that allows us to define new families of tableaux including both balanced and standard Young tableaux. We use these new objects to describe the set of reduced decompositions of any permutation. We then generalize the work of Fomin \emph{et al.} by giving, among other things, a new proof of the fact that balanced and standard tableaux are equinumerous, and by exhibiting many new families of tableaux having similar combinatorial properties to those of balanced tableaux.Comment: This new version cointains several major changes in order to take new results into accoun

A new family of posets generalizing the weak order on some Coxeter groups

We construct a poset from a simple acyclic digraph together with a valuation on its vertices, and we compute the values of its M\"obius function. We show that the weak order on Coxeter groups of type A, B, affine A, and the flag weak order on the wreath product $\mathbb{Z} \_r \wr S\_n$ introduced by Adin, Brenti and Roichman, are special instances of our construction. We conclude by associating a quasi-symmetric function to each element of these posets. In the $A$ and $\widetilde{A}$ cases, this function coincides respectively with the classical Stanley symmetric function, and with Lam's affine generalization

Pay-as-you-go Social Security and the aging of America: an economic analysis

Because it is a mature pay-as-you-go retirement system, Social Security provides current and future workers with below-market returns. These workers bear the burden of the unfunded liability arising from windfall gains to past retirees. Alan D. Viard uses these principles to examine the effects of three demographic developments: the low birthrate since the baby boom ended in 1965, the impending retirement of the baby boomers, and the downward trend in old-age mortality. The low birthrate reduces Social Security’s long-run rate of return as the unfunded liability is spread across fewer workers. The boomers’ retirement does not pose a separate problem, but marks the end of the temporary gains provided by the high birthrate during the boom. Because the downward mortality trend does not change Social Security’s long-run rate of return or the number of workers across whom the unfunded liability can be spread, it need not change any worker’s burden. However, policy responses to the trend are likely to shift burdens from earlier generations to later ones.Social security

The federal budget: what a difference a year makes

Monetary policy

The transition to consumption taxation, Part 2: the impact on existing financial assets

Replacing the income tax with a consumption tax is likely to reduce the total value of the capital stock. Alan D. Viard reviews how this decline is divided between bondholders and stockholders and the effect on household borrowers and lenders. He explains that the results depend on whether monetary policy accommodates the tax through a higher price level. Without accommodation, the decline in the value of capital is largely borne by stockholders and there is little reallocation of wealth between household borrowers and lenders. If the tax is fully accommodated, bondholders bear heavier burdens than stockholders and household borrowers gain at the expense of the household lenders.Taxation ; Stocks ; Monetary policy ; Wealth

The new budget outlook: policymakers respond to the surplus

Economic events and policy changes have unexpectedly moved the federal budget into surplus. If current policies are maintained, surpluses are expected to continue for twenty years, although deficits are expected to return after 2020. Congress and President Clinton are considering proposals to reduce the projected surpluses through tax cuts or spending increases. In this article, Alan Viard describes the recent budget events and the new budget outlook. He analyzes the effects of the proposed tax cuts and spending increases, finding that they are likely to reduce national saving and lower future output. He concludes that the desirability of this outcome depends on value judgments about the needs and rights of current and future generations.Budget ; Budget deficits

The welfare effects of pay-as-you-go retirement programs: the role of tax and benefit timing

It is well known that pay-as-you-go retirement programs reduce steady-state welfare and the capital stock in dynamically efficient OLG economies. The common two-period OLG model obscures, however, the dependence of these effects on the ages at which taxes are paid and benefits are received. Program changes that shift taxes to older workers or benefits to younger retirees have effects similar to reductions in program size, yielding steady-state welfare gains and increases in capital accumulation while imposing transition costs on current generations. This analysis has policy implications for both tax and benefit timing.Social security ; Fiscal policy ; Taxation

The transition to consumption taxation, part 1: the impact on existing capital

Alan Viard reviews the transitional impact on existing capital from replacing the income tax with a consumption tax. This replacement generally reduces the real value of existing capital because it does not receive the tax relief given to new investment. If the income and consumption taxes had stylized forms and capital were produced without adjustment costs, the proportional decline would equal the consumption tax rate--a 25 percent tax would uniformly reduce the value of existing capital by 25 percent. Under more realistic assumptions, however, the actual decline is likely to be smaller and less uniform and some types of capital may even increase in value. The burden on owners of existing capital is also mitigated because the tax reform increases the rate of return they earn from reinvestment.