When one considers the concept of a door, or "portal," one logically tends to think of it in terms of an opening in a wall. But the exact nature of a portal depends on what it opens onto or into -- or whether it opens at all.

Sculptor Martha Jackson-Jarvis has chosen portals as the topic of a new series constituting a large part of her installation of wall sculptures at BR Kornblatt Gallery. The insistent bifurcation between what a doorway is and what it opens onto (if it opens) is at the root of these stunning mixed-media pieces. They question the very concept of an aperture itself. (Can one, for instance, have a door in space, as opposed to a door in a fixed structure? Is a portal still a portal if it doesn't open into anything?)

Jackson-Jarvis makes her instantly recognizable compositions from bits of glazed ceramic tile, glass, copper sheeting, gilded plaster, cut and painted paper and just about anything else that comes to hand. In this artist's world, nothing is static or fixed. Hers is an art about fragments -- a kind of exploded examination of what constitutes form. This series of "Portals," arranged in a continuous display along four large walls of the gallery, is connected by a swirling pattern of black tile and orange-glazed ceramic shapes.

This artist has always treated gallery space almost as "performance" space. And this show succeeds in drawing one into a complete, seemingly mobile environment. It's not that the works fill the walls entirely. Quite the contrary; it's implicit that the flat white of the wall functions as pure space in which her complex compositions float and spin. Therein lies the intrigue of these "portals." They are, in essence, doors set in nothing, but doors nonetheless. The doors become the reference, gloriously decorative and intriguing objects though they are, and the walls on which they hang function as the grande aperture, deep space alive with whirling fragments.

Sculpture at Washington Square

At Washington Square, it's time again for the annual sculpture roundup. This year's big exhibit consists of works by 27 artists from around the country (although a disproportionate number are local); the show's jury comprised Howard Risatti of Virginia Commonwealth University, Richmond; Willem de Looper, Washington artist and former curator at the Phillips Collection; and David C. Levy, the new director of the Corcoran Gallery.

There's work here of every style, size and material. Yet, perhaps due to some tacitly agreed upon agenda by the jurors, it's not nearly as undisciplined an exhibit as some former efforts have been. There's little in the way of representational work: There are potentially "functional" objects, certainly. But for the most part the sculpture here is about form, symbolism and a modernist concern for color and space. Few of the works would have looked much out of place in a Paris gallery of, say, 60 years ago. Indeed, talented Washington area sculptor William Bennett is represented by a work that pays unblushing homage to the famous "Chariots" of Giacometti.

If anything is striking about this exhibit -- again it's tough to say if this reflects the tastes of the jurors or is representative of a nationwide trend -- it's the extent to which these artists appear to be reexamining the legacy of modernism. Most of the work is fundamentally about process and material, no matter what the subject -- and that's as varied as the interests of the artists themselves.

There is, for example, a good deal of nature-inspired work (Charles Herndon's "In Fertile Folds Outflowing"), as well as work apparently derived from ancient Celtic megaliths (David Gleeson's "Corraigh"). There are works that recall the "mechanical" drawings of Duchamp (Andrew M. Dunnill's "Tank"), and Tinguely-like metal compositions (Susan Firestone's "Interference"). In all this is rather a good show. The best things, however, are the quietest little pieces, such as Pamela Blotner's lovely wood piece, "Hold Fast."

'Evidence' at Gallery 10

The group show "Evidence of Man" at Gallery 10 is an uncommonly interesting exhibit of, for the most part, uncommonly good work. This may have something to do with the fact that artist Darrell Dean curated it. His eye for the art of others is evidently as good as it is for his own.

According to Dean, as quoted on the exhibit list, "Evidence of Man ... reflects on the imprint of the human presence" -- which is to say, man's imprint on nature, as opposed to pictures of people themselves. And, with the exception of three gorgeous, moody little encaustic images of volcanoes and night skies by John Clingempeel -- which show no evidence of man whatever -- most of the works here do an excellent job of carrying the title theme. Sherry Zvares Sanabria is of course represented, with three paintings of long-abandoned interiors from the "Ellis Island" series. There are also three of Sarah McCoubrey's stunning oil-on-panel paintings of ruins, both ancient and contemporary suburban. Shoshanna Ahart checks in with three rather nice, small, Edward Hopperish studies of dormers on old houses, and Mary Edith Alexander with an inexpertly painted but nevertheless curiously affecting picture of a spacious empty interior rendered in browns and soft golds.

Of works in the more modernist tradition are Patrick Kirwin's "A Lifetime," a heavy-handed but well-executed allegory of a sand castle being demolished by a wave, rendered in a monochromatic pointillist style, and some darkly graceful, nearly abstract pieces by Patricia O'Malley and Sarah Pitkin.

Martha Jackson-Jarvis, at BR Kornblatt Gallery, 406 Seventh St. NW, through July 13.

Sculpture '91, at Washington Square, 1050 Connecticut Ave. NW (at L Street), through Sept. 13.

Evidence of Man, at Gallery 10, 1519 Connecticut Ave. NW, through July 13.