/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.commons.math;

/**
 * Interface representing a
 * <a href="http://mathworld.wolfram.com/Field.html">field</a>.
 * <p>
 * Classes implementing this interface will often be singletons.
 * </p>
 * 
 * @param <T>
 *            the type of the field elements
 * @see FieldElement
 * @version $Revision$ $Date$
 * @since 2.0
 */
public interface Field<T> {

	/**
	 * Get the additive identity of the field.
	 * <p>
	 * The additive identity is the element e<sub>0</sub> of the field such that
	 * for all elements a of the field, the equalities a + e<sub>0</sub> =
	 * e<sub>0</sub> + a = a hold.
	 * </p>
	 * 
	 * @return additive identity of the field
	 */
	T getZero();

	/**
	 * Get the multiplicative identity of the field.
	 * <p>
	 * The multiplicative identity is the element e<sub>1</sub> of the field
	 * such that for all elements a of the field, the equalities a &times;
	 * e<sub>1</sub> = e<sub>1</sub> &times; a = a hold.
	 * </p>
	 * 
	 * @return multiplicative identity of the field
	 */
	T getOne();

}