PRAGUE, Czech Republic (AP) _ Czech senator Vaclav Benda, a mathematician, philosopher and former anti-communist dissident, died today, the news agency CTK reported. He was 52.

Benda had been hospitalized recently with serious pulmonary problems.

The agency said the speaker of the lower chamber of the Czech parliament, Vaclav Klaus, announced Benda's death at the beginning of today's parliament's session. Benda was a member of Klaus's Civic Democratic Party.

Benda, a signatory of the Charter 77 human rights movement, spent four years in communist jails.

After the 1989 peaceful revolution that toppled the communist regime, Benda became a deputy in the then-Czechoslovak parliament and later headed a newly established institute investigating crimes of the former communist nomenclature.

He was elected to the upper chamber of the Czech parliament, the Senate, in 1996.

Benda is survived by his wife, Kamila, four sons and two daughters.